STA350BW - STMicroelectronics

This is information on a product in full production.

April 2012 Doc ID 018572 Rev 3 1/86

STA350BW

Sound Terminal®

2.1-channel high-efficiency digital audio system

Datasheet − production data

Features

■Wide-range supply voltage

– 5 V to 26 V (operating range)

– 30 V (absolute maximum rating)

■Four power output configurations(a)

– 2 channels of ternary PWM (stereo mode)

(2 x 50 W into 6 Ω at 25 V)

– 3 channels - left, right using binary and LFE

using ternary PWM (2.1 mode) (2 x 18 W +

1x40W into 2x4 Ω, 1 x 8 Ω at 25 V)

– 2 channels of ternary PWM (2 x 50 W) +

stereo lineout ternary

– 1 channel of ternary PWM as mono-BTL

(1 x 90 W into 3 Ω at 24.5 V)

■FFX™ 100 dB SNR and dynamic range

■Selectable 32 to 192 kHz input sample rates

■I2C control with selectable device address

■Digital gain/attenuation +42 dB to -80 dB with

0.125 dB/step resolution

■Soft-volume update with programmable ratio

■Individual channel and master gain/attenuation

■Two independent DRCs configurable as a

dual-band anti-clipper (B2DRC) or independent

limiters/compressors

■EQ-DRC for DRC based on filtered signals

■Dedicated LFE processing for bass boosting

with 0.125 dB/step resolution

■Audio presets:

– 15 preset crossover filters

– 5 preset anti-clipping modes

– Preset nighttime listening mode

■Individual channel and master soft/hard mute

■Independent channel volume and DSP bypass

■Automatic zero-detect mute

■Automatic invalid input-detect mute

■I2S input data interface

■Input and output channel mapping

■Up to 8 user-programmable biquads per

channel

■3 coefficient banks for EQ presets storing with

fast recall via I2C interface

■Extended coefficient dynamic up to -4..4 for

easy implementation of high shelf filters

■Bass/treble tones and de-emphasis control

■Selectable high-pass filter for DC blocking

■Advanced AM interference frequency

switching and noise suppression modes

■Selectable high or low bandwidth

noise-shaping topologies

■Selectable clock input ratio

■96 kHz internal processing sample rate with

quantization error noise shaping for very low

cutoff frequency filters

■Thermal overload and short-circuit protection

embedded

■Video apps: 576 x Fs input mode supported

■Fully compatible with STA339BW and

STA339BWS

a. Music output power with THD = 10%, using ST’s recommended board, see Section 4:

Characterization curves for more details.

PowerSSO-36

with exposed pad down (EPD)

www.st.com

Contents STA350BW
2/86 Doc ID 018572 Rev 3
Contents
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
1 Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  11
Pin connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
1 Connection diagram  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  12
2 Pin description  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  12
Electrical specifications  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
1 Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  14
2 Thermal data   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  14
3 Recommended operating conditions  . . . . . . . . . . . . . . . . . . . . . . . . . . . .  15
4 Electrical specifications for the digital section   . . . . . . . . . . . . . . . . . . . . .  15
5 Electrical specifications for the power section  . . . . . . . . . . . . . . . . . . . . .  16
Characterization curves  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
1 Mono parallel BTL characteristics   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  23
Processing data paths  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
6I
2C bus specification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
1 Communication protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  27
1.1 Data transition or change . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
1.2 Start condition  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
1.3 Stop condition   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
1.4 Data input   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
2 Device addressing  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  27
3 Write operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  28
3.1 Byte write  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
3.2 Multi-byte write . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
4 Read operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  28
4.1 Current address byte read  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
4.2 Current address multi-byte read   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
4.3 Random address byte read  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

STA350BW Contents
Doc ID 018572 Rev 3 3/86
4.4 Random address multi-byte read . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
4.5 Write mode sequence  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
4.6 Read mode sequence  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Register description  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
1 Configuration register A (addr 0x00)   . . . . . . . . . . . . . . . . . . . . . . . . . . . .  33
1.1 Master clock select   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
1.2 Interpolation ratio select . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
1.3 Thermal warning recovery bypass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
1.4 Thermal warning adjustment bypass  . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
1.5 Fault detect recovery bypass  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
2 Configuration register B (addr 0x01)   . . . . . . . . . . . . . . . . . . . . . . . . . . . .  35
2.1 Serial audio input interface format  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
2.2 Serial data interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
2.3 Serial data first bit   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
2.4 Delay serial clock enable  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
2.5 Channel input mapping  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
3 Configuration register C (addr 0x02)   . . . . . . . . . . . . . . . . . . . . . . . . . . . .  39
3.1 FFX power output mode   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
3.2 FFX compensating pulse size register . . . . . . . . . . . . . . . . . . . . . . . . . . 39
3.3 Overcurrent warning detect adjustment bypass . . . . . . . . . . . . . . . . . . . 40
4 Configuration register D (addr 0x03)   . . . . . . . . . . . . . . . . . . . . . . . . . . . .  40
4.1 High-pass filter bypass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
4.2 De-emphasis  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
4.3 DSP bypass  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
4.4 Post-scale link  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
4.5 Biquad coefficient link   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
4.6 Dynamic range compression/anti-clipping bit   . . . . . . . . . . . . . . . . . . . . 41
4.7 Zero-detect mute enable  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
4.8 Submix mode enable  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
5 Configuration register E (addr 0x04)   . . . . . . . . . . . . . . . . . . . . . . . . . . . .  42
5.1 Max power correction variable  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
5.2 Max power correction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
5.3 Noise-shaper bandwidth selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
5.4 AM mode enable  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
5.5 PWM speed mode  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
5.6 Distortion compensation variable enable . . . . . . . . . . . . . . . . . . . . . . . . 43

Contents STA350BW
4/86 Doc ID 018572 Rev 3
5.7 Zero-crossing volume enable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
5.8 Soft-volume update enable   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
6 Configuration register F (addr 0x05)   . . . . . . . . . . . . . . . . . . . . . . . . . . . .  44
6.1 Output configuration   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
6.2 Invalid input detect mute enable   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
6.3 Binary output mode clock loss detection  . . . . . . . . . . . . . . . . . . . . . . . . 50
6.4 LRCK double trigger protection  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
6.5 Auto EAPD on clock loss  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
6.6 IC power-down . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
6.7 External amplifier power-down   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
7 Volume control registers (addr 0x06 - 0x0A)   . . . . . . . . . . . . . . . . . . . . . .  51
7.1 Mute/line output configuration register . . . . . . . . . . . . . . . . . . . . . . . . . . 51
7.2 Master volume register   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
7.3 Channel 1 volume   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
7.4 Channel 2 volume   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
7.5 Channel 3 / line output volume   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
8 Audio preset registers (addr 0x0B and 0x0C)   . . . . . . . . . . . . . . . . . . . . .  53
8.1 Audio preset register 1 (addr 0x0B)  . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
8.2 Audio preset register 2 (addr 0x0C) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
8.3 AM interference frequency switching  . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
8.4 Bass management crossover   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
9 Channel configuration registers (addr 0x0E - 0x10) . . . . . . . . . . . . . . . . .  55
9.1 Tone control bypass  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
9.2 EQ bypass  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
9.3 Volume bypass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
9.4 Binary output enable registers  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
9.5 Limiter select  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
9.6 Output mapping  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
10 Tone control register (addr 0x11)  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  57
10.1 Tone control  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
11 Dynamic control registers (addr 0x12 - 0x15)   . . . . . . . . . . . . . . . . . . . . .  57
11.1 Limiter 1 attack/release rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
11.2 Limiter 1 attack/release threshold  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
11.3 Limiter 2 attack/release rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
11.4 Limiter 2 attack/release threshold  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
11.5 Limiter 1 extended attack threshold (addr 0x32)  . . . . . . . . . . . . . . . . . . 61

STA350BW Contents
Doc ID 018572 Rev 3 5/86
11.6 Limiter 1 extended release threshold (addr 0x33)  . . . . . . . . . . . . . . . . . 61
11.7 Limiter 2 extended attack threshold (addr 0x34 . . . . . . . . . . . . . . . . . . ) 62
11.8 Limiter 2 extended release threshold (addr 0x35)  . . . . . . . . . . . . . . . . . 62
12 User-defined coefficient control registers (addr 0x16 - 0x26) . . . . . . . . . .  62
12.1 Coefficient address register  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
12.2 Coefficient b1 data register bits 23:16  . . . . . . . . . . . . . . . . . . . . . . . . . . 62
12.3 Coefficient b1 data register bits 15:8  . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
12.4 Coefficient b1 data register bits 7:0  . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
12.5 Coefficient b2 data register bits 23:16  . . . . . . . . . . . . . . . . . . . . . . . . . . 63
12.6 Coefficient b2 data register bits 15:8  . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
12.7 Coefficient b2 data register bits 7:0  . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
12.8 Coefficient a1 data register bits 23:16  . . . . . . . . . . . . . . . . . . . . . . . . . . 63
12.9 Coefficient a1 data register bits 15:8  . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
12.10 Coefficient a1 data register bits 7:0  . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
12.11 Coefficient a2 data register bits 23:16  . . . . . . . . . . . . . . . . . . . . . . . . . . 63
12.12 Coefficient a2 data register bits 15:8  . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
12.13 Coefficient a2 data register bits 7:0  . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
12.14 Coefficient b0 data register bits 23:16  . . . . . . . . . . . . . . . . . . . . . . . . . . 64
12.15 Coefficient b0 data register bits 15:8  . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
12.16 Coefficient b0 data register bits 7:0  . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
12.17 Coefficient write/read control register   . . . . . . . . . . . . . . . . . . . . . . . . . . 64
12.18 User-defined EQ   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
12.19 Pre-scale  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
12.20 Post-scale   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
12.21 Overcurrent post-scale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
13 Variable max power correction registers (addr 0x27 - 0x28)  . . . . . . . . . .  69
14 Variable distortion compensation registers (addr 0x29 - 0x2A)  . . . . . . . .  69
15 Fault detect recovery constant registers (addr 0x2B - 0x2C)  . . . . . . . . . .  70
16 Device status register (addr 0x2D) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  70
17 EQ coefficients and DRC configuration register (addr 0x31)  . . . . . . . . . .  71
18 Extended configuration register (addr 0x36)   . . . . . . . . . . . . . . . . . . . . . .  72
18.1 Dual-band DRC  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
18.2 EQ DRC mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
18.3 Extended post-scale range   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
18.4 Extended attack rate  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
18.5 Extended BIQUAD selector  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

Contents STA350BW
6/86 Doc ID 018572 Rev 3
19 EQ soft-volume configuration registers (addr 0x37 - 0x38)  . . . . . . . . . . .  75
20 DRC RMS filter coefficients (addr 0x39-0x3E) . . . . . . . . . . . . . . . . . . . . .  76
21 Extra volume resolution configuration registers (address 0x3F)   . . . . . . .  77
22 Quantization error noise correction (address 0x48)  . . . . . . . . . . . . . . . . .  78
23 Extended coefficient range up to -4...4 (address 0x49, 0x4A)  . . . . . . . . .  79
24 Miscellaneous registers (address 0x4B, 0x4C)   . . . . . . . . . . . . . . . . . . . .  80
24.1 Rate powerdown enable (RPDNEN) bit (address 0x4B, bit D7)   . . . . . . 80
24.2 Noise-shaping on DC cut filter enable (NSHHPEN) bit (address 0x4B, bit 
D6) 80
24.3 Bridge immediate off (BRIDGOFF) bit (address 0x4B, bit D5)   . . . . . . . 80
24.4 Channel PWM enable (CPWMEN) bit (address 0x4B, bit D2) . . . . . . . . 81
24.5 Power-down delay selector (PNDLSL[2:0]) bits 
(address 0x4C, bit D4, D3, D2)  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
Package thermal characteristics  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
Package mechanical data  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
Revision history   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

STA350BW List of tables
Doc ID 018572 Rev 3 7/86
List of tables
Table 1. Pin description  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Table 2. Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Table 3. Thermal data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Table 4. Recommended operating conditions  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Table 5. Electrical specifications - digital section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Table 6. Electrical specifications - power section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Table 7. Register summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Table 8. Master clock select . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Table 9. Input sampling rates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Table 10. Internal interpolation ratio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Table 11. IR bit settings as a function of input sample rate  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Table 12. Thermal warning recovery bypass  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Table 13. Thermal warning adjustment bypass  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Table 14. Fault detect recovery bypass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Table 15. Serial audio input interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Table 16. Serial data first bit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Table 17. Support serial audio input formats for MSB-first (SAIFB = 0) . . . . . . . . . . . . . . . . . . . . . . . 36
Table 18. Supported serial audio input formats for LSB-first (SAIFB = 1)  . . . . . . . . . . . . . . . . . . . . . 37
Table 19. Delay serial clock enable  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Table 20. Channel input mapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Table 21. FFX power output mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Table 22. Output modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Table 23. FFX compensating pulse size bits  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Table 24. Compensating pulse size . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Table 25. Overcurrent warning bypass. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Table 26. High-pass filter bypass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Table 27. De-emphasis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Table 28. DSP bypass  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Table 29. Post-scale link. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Table 30. Biquad coefficient link . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Table 31. Dynamic range compression/anti-clipping bit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Table 32. Zero-detect mute enable. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Table 33. Submix mode enable  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Table 34. Max power correction variable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Table 35. Max power correction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Table 36. Noise-shaper bandwidth selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Table 37. AM mode enable. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Table 38. PWM speed mode  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Table 39. Distortion compensation variable enable  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Table 40. Zero-crossing volume enable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Table 41. Soft-volume update enable. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Table 42. Output configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Table 43. Output configuration engine selection  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Table 44. Invalid input detect mute enable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Table 45. Binary output mode clock loss detection  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Table 46. LRCK double trigger protection  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Table 47. Auto EAPD on clock loss  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Table 48. IC power-down . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

List of tables STA350BW
8/86 Doc ID 018572 Rev 3
Table 49. External amplifier power-down . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Table 50. Line output configuration  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Table 51. Master volume offset as a function of MV[7:0] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
Table 52. Channel volume as a function of CxV[7:0] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Table 53. Audio preset gain compression/limiters selection for AMGC[3:2] = 00. . . . . . . . . . . . . . . . 53
Table 54. AM interference frequency switching bits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
Table 55. Audio preset AM switching frequency selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
Table 56. Bass management crossover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
Table 57. Bass management crossover frequency  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
Table 58. Tone control bypass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
Table 59. EQ bypass  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
Table 60. Binary output enable registers  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
Table 61. Channel limiter mapping as a function of CxLS bits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
Table 62. Channel output mapping as a function of CxOM bits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
Table 63. Tone control boost/cut as a function of BTC and TTC bits . . . . . . . . . . . . . . . . . . . . . . . . . 57
Table 64. Limiter attack rate as a function of LxA bits  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
Table 65. Limiter release rate as a function of LxR bits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
Table 66. Limiter attack threshold as a function of LxAT bits (AC-mode). . . . . . . . . . . . . . . . . . . . . . 60
Table 67. Limiter release threshold as a function of LxRT bits (AC-mode)  . . . . . . . . . . . . . . . . . . . . 60
Table 68. Limiter attack threshold as a function of LxAT bits (DRC -mode) . . . . . . . . . . . . . . . . . . . . 61
Table 69. Limiter release threshold as a as a function of LxRT bits (DRC-mode) . . . . . . . . . . . . . . . 61
Table 70. RAM block for biquads, mixing, scaling and bass management. . . . . . . . . . . . . . . . . . . . . 68
Table 71. Status register bits  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
Table 72. EQ RAM select . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
Table 73. Anti-clipping and DRC preset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
Table 74. Anti-clipping selection for AMGC[3:2] = 01 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
Table 75. Biquad filter settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
Table 76. PowerSSO-36 EPD dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
Table 77. Document revision history  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

STA350BW List of figures
Doc ID 018572 Rev 3 9/86
List of figures
Figure 1. Block diagram   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Figure 2. Pin connection PowerSSO-36 (top view) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Figure 3. Test circuit  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Figure 4. Demonstration board, 2.0 channels  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Figure 5. Mono parallel BTL schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Figure 6. THD+N vs. output power (VCC = 25 V, load = 6 Ω)  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Figure 7. THD+N vs. output power (VCC = 18 V, load = 8 Ω)  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Figure 8. Output power vs. VCC (load = 6 Ω) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Figure 9. Output power vs. VCC (load = 8 Ω) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Figure 10. Efficiency vs. output power (VCC = 25 V, load = 6 Ω) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Figure 11. Efficiency vs. output power (VCC = 25 V, load = 8 Ω) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Figure 12. THD+N vs. output power (VCC = 25 V, load = 3 Ω)  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Figure 13. Output power vs. VCC (load = 3 Ω) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Figure 14. Efficiency vs. output power (VCC = 26 V, load = 3 Ω) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Figure 15. Efficiency vs. output power (VCC = 18 V, load = 3 Ω) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Figure 16. Left and right processing - part 1  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Figure 17. Processing - part 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Figure 18. Write mode sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Figure 19. Read mode sequence. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Figure 20. OCFG = 00 (default value) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Figure 21. OCFG = 01   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Figure 22. OCFG = 10   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Figure 23. OCFG = 11   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Figure 24. Output mapping scheme  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Figure 25. 2.0 channels (OCFG = 00) PWM slots   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Figure 26. 2.1 channels (OCFG = 01) PWM slots   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Figure 27. 2.1 channels (OCFG = 10) PWM slots   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Figure 28. Basic limiter and volume flow diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
Figure 29. B2DRC scheme  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
Figure 30. EQDRC scheme   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
Figure 31. Extra resolution volume scheme. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
Figure 32. Biquad filter structure with quantization error noise-shaping  . . . . . . . . . . . . . . . . . . . . . . . 79
Figure 33. Double-layer PCB with 2 copper ground areas and 24 via holes   . . . . . . . . . . . . . . . . . . . 82
Figure 34. PowerSSO-36 power derating curve  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
Figure 35. PowerSSO-36 EPD outline drawing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

Description STA350BW

10/86 Doc ID 018572 Rev 3

1 Description

The STA350BW is an integrated solution of digital audio processing, digital amplifier control,

and FFX-power output stage, thereby creating a high-power single-chip FFX™ solution

comprising high-quality, high-efficiency, and all-digital amplification.

The STA350BW is based on an FFX (fully flexible amplification) processor, a proprietary

technology from STMicroelectronics. FFX is the evolution and the enlargement of ST’s

ternary technology: the new processor can be configured to work in ternary, binary, binary

differential and phase-shift PWM modulation schemes.

The STA350BW contains the ternary, binary and binary differential implementations, a

subset of the full capability of the FFX processor.

The STA350BW is part of the Sound Terminal® family that provides full digital audio

streaming to the speaker, offering cost effectiveness, low power dissipation and sound

enrichment.

The STA350BW power section consists of four independent half-bridges. These can be

configured via digital control to operate in different modes. 2.1 channels can be provided by

two half-bridges and a single full-bridge, providing up to 2 x 18 W + 1 x 40 W of music output

power, by using standard 4 and 8 Ω speakers. Two channels can be provided by two full-

bridges, providing up to 2 x 50 W of music power, by using standard 6 Ω speaker or

2 x 40 W by using 8 Ω speakers at 25 V. The IC can also be configured as 2.1 channels with

2 x 40 W provided by the device and external power for FFX power drive. If configured as

mono-BTL, the latter is capable of providing up to 1 x 90 W on a standard 3 Ω load or

1 x 75 W by using a 4 Ω, setting the supply voltage at 25 V. Please refer to the package

thermal characteristics and application suggestions for more details.

Also provided in the STA350BW are a full assortment of digital processing features. This

includes up to 8 programmable biquads (EQ) per channel. Special digital signal processing

techniques are available in order to manage low-frequency quantization noise in case of

very low frequency cutoff filter thresholds. The coefficient range -4..4 allows the easy

implementation of high shelf filters. Available presets allow the advantage of earlier time-to-

market by substantially reducing the amount of software development needed for certain

functions. This includes audio preset volume loudness, preset volume curves and preset EQ

settings. There are also new advanced AM radio interference reduction modes. Dual-band

DRC dynamically equalizes the system to provide speaker linear frequency response

regardless of output power level. This feature independently processes the two bands,

controlling dynamically the output power level in each band and so providing better sound

clarity.

The serial audio data input interface accepts all possible formats, including the popular I2S

format. Three channels of FFX processing are provided. This high-quality conversion from

PCM audio to FFX PWM switching waveform provides over 100 dB SNR and dynamic

range.

STA350BW Description

Doc ID 018572 Rev 3 11/86

1.1 Block diagram

Figure 1. Block diagram

Pro tection

curre nt/the rm al

Log ic

Regulators

Bias

Power

contro l

FFX

PLL

Vo lume

control

Channel

Chann el

Ch anne l

Chann el

I2S

in ter face

PowerDigita l DSP

I2C

AM045167v1

Pin connections STA350BW

12/86 Doc ID 018572 Rev 3

2 Pin connections

2.1 Connection diagram

Figure 2. Pin connection PowerSSO-36 (top view)

2.2 Pin description

VDD_DIG

GND_DIG

SCL

SDA

INT_LINE

RESET

SDI

LRCKI

BICKI

XTI

GND_PLL

FILTER_PLL

VDD_PLL

PWRDN

GND_DIG

VDD_DIG

TWARN/OUT4A

EAPD/OUT4B

GND_SUB

TEST_MODE

VSS

VCC_REG

OUT2B

GND2

VCC2

OUT2A

OUT1B

VCC1

GND1

OUT1A

GND_REG

VDD

CONFIG

OUT3B/FFX3B

OUT3A/FFX3A

D05AU1638 AM045168v1

Table 1. Pin description

Pin Type Name Description

1 GND GND_SUB Substrate ground

2I SA I

C select address (pull-down)

3 I TEST_MODE This pin must be connected to ground (pull-down)

4 I/O VSS Internal reference at Vcc-3.3 V

5 I/O VCC_REG Internal Vcc reference

6 O OUT2B Output half-bridge 2B

7 GND GND2 Power negative supply

8 Power VCC2 Power positive supply

9 O OUT2A Output half-bridge 2A

10 O OUT1B Output half-bridge 1B

STA350BW Pin connections

Doc ID 018572 Rev 3 13/86

11 Power VCC1 Power positive supply

12 GND GND1 Power negative supply

13 O OUT1A Output half-bridge 1A

14 GND GND_REG Internal ground reference

15 Power VDD Internal 3.3 V reference voltage

16 I CONFIG Parallel mode command

17 O OUT3B/FFX3B PWM out CH3B / external bridge driver

18 O OUT3A/FFX3A PWM out CH3A / external bridge driver

19 O EAPD/OUT4B Power-down for external bridge / PWM out CH4B

20 I/O TWARN/OUT4A Thermal warning from external bridge (pull-up when input)

/ PWM out CH4A

21 Power VDD_DIG Digital supply voltage

22 GND GND_DIG Digital ground

23 I PWRDN Power down (pull-up)

24 Power VDD_PLL Positive supply for PLL

25 I FILTER_PLL Connection to PLL filter

26 GND GND_PLL Negative supply for PLL

27 I XTI PLL input clock

28 I BICKI I

S serial clock

29 I LRCKI I

S left/right clock

30 I SDI I

S serial data channels 1 and 2

31 I RESET Reset (pull-up)

32 O INT_LINE Fault interrupt

33 I/O SDA I

C serial data

34 I SCL I

C serial clock

35 GND GND_DIG Digital ground

36 Power VDD_DIG Digital supply voltage

Table 1. Pin description (continued)

Pin Type Name Description

Electrical specifications STA350BW

14/86 Doc ID 018572 Rev 3

3 Electrical specifications

3.1 Absolute maximum ratings

Warning: Stresses beyond those listed in Table 2 above may cause

permanent damage to the device. These are stress ratings

only, and functional operation of the device at these or any

other conditions beyond those indicated under

“Recommended operating conditions” are not implied.

Exposure to AMR conditions for extended periods may affect

device reliability. In the real application, power supplies with

nominal values rated within the recommended operating

conditions may rise beyond the maximum operating

conditions for a short time when no or very low current is

sunk (amplifier in mute state). In this case the reliability of the

device is guaranteed, provided that the absolute maximum

ratings are not exceeded.

3.2 Thermal data

Table 2. Absolute maximum ratings

Symbol Parameter Min Typ Max Unit

Vcc Power supply voltage (VCCxA, VCCxB) -0.3 30 V

VDD_DIG Digital supply voltage -0.3 4 V

VDD_PLL PLL supply voltage -0.3 4

Top Operating junction temperature -20 150 °C

Tstg Storage temperature -40 150 °C

Table 3. Thermal data

Symbol Parameter Min Typ Max Unit

Rth j-case Thermal resistance junction-case (thermal pad) 1.5 °C/W

Tth-sdj Thermal shutdown junction temperature 150 °C

Tth-w Thermal warning temperature 130 °C

Tth-sdh Thermal shutdown hysteresis 20 °C

Rth j-amb Thermal resistance junction-ambient (1)

1. See Section 8: Package thermal characteristics on page 82 for details.

STA350BW Electrical specifications

Doc ID 018572 Rev 3 15/86

3.3 Recommended operating conditions

3.4 Electrical specifications for the digital section

Table 4. Recommended operating conditions

Symbol Parameter Min Typ Max Unit

Vcc Power supply voltage (VCCxA, VCCxB) 5 26 V

VDD_DIG Digital supply voltage 2.7 3.3 3.6 V

VDD_PLL PLL supply voltage 2.7 3.3 3.6 V

Tamb Ambient temperature -20 +85 °C

Table 5. Electrical specifications - digital section

Symbol Parameter Conditions Min Typ Max Unit

Iil

Low-level input current without

pull-up/down device Vi = 0 V 1 5 µA

Iih

High-level input current without

pull-up/down device

Vi = VDD_DIG

= 3.6 V 15µA

Vil Low-level input voltage 0.2 *

VDD_DIG V

Vih High-level input voltage 0.8 *

VDD_DIG V

Vol Low-level output voltage Iol=2 mA 0.4 *

VDD_DIG V

Voh High-level output voltage Ioh=2 mA 0.8 *

VDD_DIG V

Ipu Pull-up/down current 25 66 125 µA

Rpu

Equivalent pull-up/down

resistance 50 kΩ

Electrical specifications STA350BW

16/86 Doc ID 018572 Rev 3

3.5 Electrical specifications for the power section

The specifications given in this section are valid for the operating conditions: VCC =24V,

f=1kHz, f

sw = 384 kHz, Tamb = 25° C and RL = 8 Ω, unless otherwise specified.

Table 6. Electrical specifications - power section

Symbol Parameter Conditions Min Typ Max Unit

Continuous output power, BTL, ternary

mode

THD = 1% 27 W

THD = 10% 36

Continuous output power SE, binary

mode, RL = 4 Ω

THD = 1% 12 W

THD = 10% 15.5

RdsON

Power Pchannel/Nchannel MOSFET (total

bridge) ld = 1.5 A 180 250 mΩ

Idss Power Pchannel/Nchannel leakage VCC = 20 V 10 μA

ILDT Low current dead time (static) Resistive load(1) 8 15 ns

IHDT High current dead time (dynamic) I load(1) = 1.5 A 15 30 ns

trRise time Resistive load(1) 10 18 ns

tfFall time Resistive load(1) 10 18 ns

Vcc Supply voltage operating voltage 5 26 V

Ivcc

Supply current from Vcc in power-down PWRDN = 0 1 μA

Supply current from Vcc in operation

PCM input signal

= -60 dBfs,

Switching frequency

= 384 kHz,

No LC filters

52 60 mA

Ivdd

Supply current FFX processing (reference

only)

Internal clock =

49.152 MHz 55 70 mA

Ilim Overcurrent limit (2) 3.0 3.8 4.0 A

Isc Short-circuit protection Hi-Z output 4.0 5.0 A

UVL Undervoltage protection 4.3 V

OVP Overvoltage protection 29 V

tmin Output minimum pulse width No load 100 ns

DR Dynamic range 100 dB

SNR Signal-to-noise ratio, ternary mode A-Weighted 100 dB

Signal-to-noise ratio binary mode 90 dB

THD+N Total harmonic distortion + noise

FFX stereo mode,

Po = 1 W

f=1kHz

0.09 %

STA350BW Electrical specifications

Doc ID 018572 Rev 3 17/86

Figure 3. Test circuit

XTA L K Crosstalk

FFX stereo mode,

<5 kHz

One channel driven

at 1 W

Other channel

measured

80 dB

PSRR Power Supply Rejection Ratio

FFX stereo mode,

<5 kHz

VRipple01V RMS

Audio input = dither

only

80 dB

Peak efficiency, FFX mode Po = 2 x 25 W

into 8 Ω90

Peak efficiency, binary modes Po = 2 x 10W into 4Ω

+ 1 x 20W into 8 Ω86

1. Refer to Figure 3: Test circuit.

2. Limit current if the register (OCRB Section 7.3.3) overcurrent warning detect adjustment bypass is enabled. When disabled

refer to the Isc.

Table 6. Electrical specifications - power section (continued)

Symbol Parameter Conditions Min Typ Max Unit

tr tf

VCC

0.9*VCC

VCC/2

0.1*VCC

OUTxY

+VCC

Duty cycle = 50%

INxY

OUTxY

GND

vdc = VCC/2

R= 8Ω

Low current dead tim e = M AX(tr,tf)

tr tf

VCC

0.9*VCC

VCC/2

0.1*VCC

OUTxY

+VCC

Duty cycle = 50%

INxY

OUTxY

GND

vdc = VCC/2

R= 8Ω

Low current dead tim e = M AX(tr,tf)

AM045169v1

Characterization curves STA350BW

18/86 Doc ID 018572 Rev 3

4 Characterization curves

The following characterization curves were made using the STA350BW demonstration

board with 2.0 channels (refer to the schematic in Figure 6) under the following test

conditions:

VCC = 25 V, f = 1 kHz, fSW = 384 kHz, Tamb = 25 °C and RL = 6 Ω, unless otherwise

specified.

Figure 4. Demonstration board, 2.0 channels

AM045290v1

STA350BW Characterization curves

Doc ID 018572 Rev 3 19/86

Figure 5. Mono parallel BTL schematic

AM045170v1

Characterization curves STA350BW

20/86 Doc ID 018572 Rev 3

Figure 6. THD+N vs. output power (VCC = 25 V, load = 6 Ω)

Figure 7. THD+N vs. output power (VCC = 18 V, load = 8 Ω)

0.01

0.02

0.05

0.1

0.2

0.5

1m 1002m 5m 10m 20m 50m 100m 200m 500m 1 2 5 10 20 50

Vcc=25V , Load = 6Ω,

Freq= 1KHz

AM045171v1

0.01

0.02

0.05

0.1

0.2

0.5

1m 502m 5m 10m 20m 50m 100m 200m 500m 1 2 5 10 20

Vcc=18V , Load = 8Ω,

Freq= 1KHz

AM045172v1

STA350BW Characterization curves

Doc ID 018572 Rev 3 21/86

Figure 8. Output power vs. VCC (load = 6 Ω)

Figure 9. Output power vs. VCC (load = 8 Ω)

+6 +26+8 +10 +12 +14 +16 +18 +20 +22 +24

Vdc

THD = 10%

THD = 1%

Load= 6 Ω,

Freq=1KHz

AM045173v1

+6 +26+8 +10 +12 +14 +16 +18 +20 +22 +24

Vdc

Load= 8 Ω,

Freq=1KHz

THD = 10%

THD = 1%

AM045174v1

Characterization curves STA350BW

22/86 Doc ID 018572 Rev 3

Figure 10. Efficiency vs. output power (VCC = 25 V, load = 6 Ω)

Figure 11. Efficiency vs. output power (VCC = 25 V, load = 8 Ω)

+0.1

+0.2

+0.3

+0.4

+0.5

+0.6

+0.7

+0.8

+0.9

55510 15 20 25 30 35 40 45 50

Vcc= 25V,

Load= 6 Ω,

Freq=1KHz

AM045175v1

η %

+0.1

+0.2

+0.3

+0.4

+0.5

+0.6

+0.7

+0.8

+0.9

54510 15 20 25 30 35 40

Vcc= 25V,

Load= 8 Ω,

Freq=1KHz

AM045176v1

η %

STA350BW Characterization curves

Doc ID 018572 Rev 3 23/86

4.1 Mono parallel BTL characteristics

Figure 12. THD+N vs. output power (VCC = 25 V, load = 3 Ω)

Figure 13. Output power vs. VCC (load = 3 Ω)

0.01

0.02

0.05

0.1

0.2

0.5

1m 1002m 5m 10m 20m 50m 100m 200m 500m 1 2 5 10 20 50

Vcc=25V

Load= 3 Ω,

Freq=1KHz

AM045177v1

110

100

+6 +26+8 +10 +12 +14 +16 +18 +20 +22 +24

Vdc

Load= 3 Ω,

Freq=1KHz

THD=10%

THD=1%

AM045178v1

Characterization curves STA350BW

24/86 Doc ID 018572 Rev 3

Figure 14. Efficiency vs. output power (VCC = 26 V, load = 3 Ω)

Figure 15. Efficiency vs. output power (VCC = 18 V, load = 3 Ω)

+0.1

+0.2

+0.3

+0.4

+0.5

+0.6

+0.7

+0.8

+0.9

10 11020 30 40 50 60 70 80 90 100

Vcc= 26V

Load= 3 Ω,

Freq=1KHz

η %

AM045179v1

+0.1

+0.2

+0.3

+0.4

+0.5

+0.6

+0.7

+0.8

+0.9

55010 15 20 25 30 35 40 45

Vcc=18V

Load= 3 Ω,

Freq=1KHz

AM045180v1

η %

STA350BW Processing data paths

Doc ID 018572 Rev 3 25/86

5 Processing data paths

Figure 16 and 17 illustrate the data processing paths inside the STA350BW.

The whole processing chain is composed of two consecutive sections. In the first one dual-

channel processing is implemented, as described below, and then each channel is fed into

the post-mixing block allowing to generate either a third channel (typically used in 2.1 output

configuration and with crossover filters enabled) or to have the channels processed by the

dual-band DRC block (2.0 output configuration with crossover filters used to define the cutoff

frequency of the two bands).

The first section begins with a 2x oversampling FIR filter allowing for 2*Fs audio processing.

Then a selectable high-pass filter removes the DC level (enabled if HFB=0).

The channel 1 and 2 processing chain can include up to 8 filters, depending on the selected

configuration (bits BQL, BQ5, BQ6, BQ7 and XO[3:0]).

By default 4 independent filters per channel are enabled, plus the pre-configured De-

Emphasis, Bass and Treble controls (BQL=0, BQ5=0, BQ6=0, BQ7=0).

If the coefficient sets are linked (BQL=1) it’s then possible to use De-Emphasis, Bass and

Treble filter in a user-defined configuration (provided the relevant BQx bits are set). In other

words both channels will use the same processing coefficients and can have up to 7 filters

each. Note that if BQL=0 the BQx bits are ignored and the 5th, 6th and 7th filters are

configured as, respectively, De-Emphasis, Bass and Treble controls.

Moreover the common 8th filter, from the subsequent processing section, can be available

on both channels (provided the pre-defined crossover frequencies are not used, XO[3:0]=0,

and the dual-band DRC is not used).

In the second section mixing and crossover filters are available. If B2DRC is not enabled

(Figure 17), they are fully user-programmable and allow generating a third channel (2.1

outputs). Alternatively, in B2DRC mode, those blocks will be used to split the sub-band and

define the cutoff frequencies of the two bands. A prescaler and a final post scaler allow full

control over the signal dynamic respectively before and after the filtering stages. A mixer

function is also available.

Figure 16. Left and right processing - part 1

From

I2S input

interface

PreScale Hi-Pass

Filter

Biquad

If HPB=0 User Defined Filters

If DSPB=0 and C1EQBP=0

FIR

over

Sampling

frequency=Fs

Sampling

frequency=2xFs

From

I2S input

interface

PreScale Hi-Pass

Filter

Biquad

#4 De-Emph.

If DEMP=0

FIR

over

sampling

Sampling

frequency=Fs

Sampling

frequency=2xFs

Bass Treble

If C1TCB=0

BTC: Bass Boost/Cut

TTC: Treble Boost/Cut

PreScale Hi-Pass

Filter

Biquad

If HPB=0 User Defined Filters

If DSPB=0 and C2EQBP=0

FIR

over

PreScale Hi-Pass

Filter

Biquad

#4 De-Emph.

If DEMP=0

FIR

over

sampling

Bass Treble

If C2TCB=0

BTC: Bass Boost/Cut

TTC: Treble Boost/Cut

If BQ5=1

and BQL=1

Biquad

If BQ6=1

and BQL=1

Biquad

IF BQ7=1

and BQL=1

Biquad

If BQ5=1

and BQL=1

Biquad

If BQ6=1

and BQL=1

Biquad

IF BQ7=1

and BQL=1

Biquad

AM045181v1

Processing data paths STA350BW

26/86 Doc ID 018572 Rev 3

Figure 17. Processing - part 2

Crossover Frequency determined by XO Setting

User Defined If XO=0000

C1Mx2

C2Mx1

C2Mx2

C3Mx1

C3Mx2

C1Mx1

Hi-Pass XO

Filter

Hi-Pass XO

Filter

User-Defined Mix Coefficients

Postscale

User Defined If XO=0000

C1Mx2=

0x00000

C2Mx1=

0x000000

C2Mx2=

0x7fffff

C3Mx1=

0x40000

C3Mx2=

0x400000

C1Mx1=

0x7fffff

B2DRC

Hi-pass

filter

User-Defined Mix Coefficients

Postscale

Vol

And

Limiter

DRC1

DRC2

CH1

Volume

CH2

Volume

CH3

Volume

B2DRC

Hi-pass

filter

DRC2

CH3

Volume

Crossover Frequency determined by XO Setting

User Defined If XO=0000

C1Mx2

C2Mx1

C2Mx2

C3Mx1

C3Mx2

C1Mx1

Hi-Pass XO

Filter

Hi-Pass XO

Filter

Lo-Pass XO

Filter

User-Defined Mix Coefficients

Vol

And

Limiter

Vol

And

Limiter

Vol

And

Limiter

Postscale

User Defined If XO=0000

C1Mx2

C2Mx1

C2Mx2

C3Mx1

C3Mx2

C1Mx1

Channel ½

Biquad#5

--------------

Hi-pass XO

filter

User-Defined Mix Coefficients

Vol

And

Limiter

Vol

And

Limiter

Vol

And

Limiter

Postscale

Channel ½

Biquad#5

--------------

Hi-pass XO

filter

Channel 3

Biquad

--------------

Low-pass XO

filter

B2DRC Disabled

Dual-band DRC enabled

Dual-band DRC disabled

AM045182v1

STA350BW I2C bus specification

Doc ID 018572 Rev 3 27/86

6 I2C bus specification

The STA350BW supports the I2C protocol via the input ports SCL and SDA_IN (master to

slave) and the output port SDA_OUT (slave to master). This protocol defines any device that

sends data to the bus as a transmitter and any device that reads the data as a receiver. The

device that controls the data transfer is known as the master and the other as the slave. The

master always starts the transfer and provides data to the serial clock for synchronization.

The STA350BW is always a slave device in all of its communications. It supports up to

400 kb/sec rate (fast-mode bit rate). The STA350BW I2C is a slave-only interface. The I2C

interface works properly only in the case that the master clock generated by the PLL has a

frequency 10 times higher compared to the frequency of the applied SCL signal.

6.1 Communication protocol

6.1.1 Data transition or change

Data changes on the SDA line must only occur when the SCL clock is low. An SDA transition

while the clock is high is used to identify a START or STOP condition.

6.1.2 Start condition

START is identified by a high-to-low transition of the data bus SDA signal while the clock

signal SCL is stable in the high state. A START condition must precede any command for

data transfer.

6.1.3 Stop condition

STOP is identified by a low-to-high transition of the data bus SDA signal while the clock

signal SCL is stable in the high state. A STOP condition terminates communication between

the STA350BW and the bus master.

6.1.4 Data input

During data input the STA350BW samples the SDA signal on the rising edge of clock SCL.

For correct device operation the SDA signal must be stable during the rising edge of the

clock and the data can change only when the SCL line is low.

6.2 Device addressing

To start communication between the master and the STA350BW, the master must initiate a

start condition. Following this, the master sends 8 bits (MSB first) corresponding to the

device select address and read or write mode to the SDA line.

The seven most significant bits are the device address identifiers, corresponding to the I2C

bus definition. In the STA350BW the I2C interface has two device addresses depending on

the SA port configuration, 0x38 when SA = 0, and 0x3A when SA = 1.

The eighth bit (LSB) identifies the read or write operation RW, this bit is set to 1 in read

mode and to 0 for write mode. After a START condition the STA350BW identifies on the bus

the device address and if a match is found, it acknowledges the identification on the SDA

I2C bus specification STA350BW

28/86 Doc ID 018572 Rev 3

bus during the 9th bit time. The byte following the device identification byte is the internal

space address.

6.3 Write operation

Following the START condition the master sends a device select code with the RW bit set

to 0. The STA350BW acknowledges this and then writes the byte of the internal address.

After receiving the internal byte address the STA350BW again responds with an

acknowledgement.

6.3.1 Byte write

In the byte write mode the master sends one data byte which is acknowledged by the

STA350BW. The master then terminates the transfer by generating a STOP condition.

6.3.2 Multi-byte write

The multi-byte write modes can start from any internal address. The master generating a

STOP condition terminates the transfer.

6.4 Read operation

6.4.1 Current address byte read

Following the START condition the master sends a device select code with the RW bit set

to 1. The STA350BW acknowledges this and then responds by sending one byte of data.

The master then terminates the transfer by generating a STOP condition.

6.4.2 Current address multi-byte read

The multi-byte read modes can start from any internal address. Sequential data bytes are

read from sequential addresses within the STA350BW. The master acknowledges each

data byte read and then generates a STOP condition, terminating the transfer.

6.4.3 Random address byte read

Following the START condition the master sends a device select code with the RW bit set

to 0. The STA350BW acknowledges this and then the master writes the internal address

byte. After receiving the internal byte address, the STA350BW again responds with an

acknowledgement. The master then initiates another START condition and sends the device

select code with the RW bit set to 1. The STA350BW acknowledges this and then responds

by sending one byte of data. The master then terminates the transfer by generating a STOP

condition.

6.4.4 Random address multi-byte read

The multi-byte read modes can start from any internal address. Sequential data bytes are

read from sequential addresses within the STA350BW. The master acknowledges each

data byte read and then generates a STOP condition, terminating the transfer.

STA350BW I2C bus specification

Doc ID 018572 Rev 3 29/86

6.4.5 Write mode sequence

Figure 18. Write mode sequence

6.4.6 Read mode sequence

Figure 19. Read mode sequence

DEV-ADDR

ACK

START RW

SUB-ADDR

ACK

DATA IN

ACK

STOP

BYTE

WRITE

DEV-ADDR

ACK

START RW

SUB-ADDR

ACK

DATA IN

ACK

STOP

MULTIBYTE

WRITE

DATA IN

ACK

DEV-ADDR

ACK

START RW

SUB-ADDR

ACK

DATA IN

ACK

STOP

BYTE

WRITE

DEV-ADDR

ACK

START RW

SUB-ADDR

ACK

DATA IN

ACK

STOP

MULTIBYTE

WRITE

DATA IN

ACK

AM045183v1

DEV-ADDR

ACK

START RW

DATA

NO ACK

STOP

CURRENT

ADDRESS

READ

DEV-ADDR

ACK

START RW

SUB-ADDR

ACK

DEV-ADDR

ACK

STOP

RANDOM

ADDRESS

READ

DATA

NO ACK

WRTRATS

DEV-ADDR

ACK

START

DATA

ACK

DATA

ACK

STOP

SEQUENTIAL

CURRENT

READ

DATA

NO ACK

DEV-ADDR

ACK

START RW

SUB-ADDR

ACK

DEV-ADDR

ACK

SEQUENTIAL

RANDOM

READ

DATA

ACK

WRTRATS

DATA

ACK NO ACK

STOP

DATA

RW=

HIGH

DEV-ADDR

ACK

START RW

DATA

NO ACK

STOP

CURRENT

ADDRESS

READ

DEV-ADDR

ACK

START RW

SUB-ADDR

ACK

DEV-ADDR

ACK

STOP

RANDOM

ADDRESS

READ

DATA

NO ACK

WRTRATS

DEV-ADDR

ACK

START

DATA

ACK

DATA

ACK

STOP

SEQUENTIAL

CURRENT

READ

DATA

NO ACK

DEV-ADDR

ACK

START RW

SUB-ADDR

ACK

DEV-ADDR

ACK

SEQUENTIAL

RANDOM

READ

DATA

ACK

WRTRATS

DATA

ACK NO ACK

STOP

DATA

RW=

HIGH

AM045184v1

30/86 Doc ID 018572 Rev 3

7 Register description

Table 7. Register summary

Addr Name D7 D6 D5 D4 D3 D2 D1 D0

0x00 CONFA FDRB TWAB TWRB IR1 IR0 MCS2 MCS1 MCS0

0x01 CONFB C2IM C1IM DSCKE SAIFB SAI3 SAI2 SAI1 SAI0

0x02 CONFC OCRB CSZ3 CSZ2 CSZ1 CSZ0 OM1 OM0

0x03 CONFD SME ZDE DRC BQL PSL DSPB DEMP HPB

0x04 CONFE SVE ZCE DCCV PWMS AME NSBW MPC MPCV

0x05 CONFF EAPD PWDN ECLE LDTE BCLE IDE OCFG1 OCFG0

0x06 MUTE/LOC LOC1 LOC0 Reserved Reserved C3M C2M C1M MMUTE

0x07 MVOL MV7 MV6 MV5 MV4 MV3 MV2 MV1 MV0

0x08 C1VOL C1V7 C1V6 C1V5 C1V4 C1V3 C1V2 C1V1 C1V0

0x09 C2VOL C2V7 C2V6 C2V5 C2V4 C2V3 C2V2 C2V1 C2V0

0x0A C3VOL C3V7 C3V6 C3V5 C3V4 C3V3 C3V2 C3V1 C3V0

0x0B AUTO1 Reserved Reserved AMGC1 AMGC0 Reserved Reserved Reserved Reserved

0x0C AUTO2 XO3 XO2 XO1 XO0 AMAM2 AMAM1 AMAM0 AMAME

0x0D AUTO3 Reserved

0x0E C1CFG C1OM1 C1OM0 C1LS1 C1LS0 C1BO C1VBP C1EQBP C1TCB

0x0F C2CFG C2OM1 C2OM0 C2LS1 C2LS0 C2BO C2VBP C2EQBP C2TCB

0x10 C3CFG C3OM1 C3OM0 C3LS1 C3LS0 C3BO C3VBP Reserved Reserved

0x11 TONE TTC3 TTC2 TTC1 TTC0 BTC3 BTC2 BTC1 BTC0

0x12 L1AR L1A3 L1A2 L1A1 L1A0 L1R3 L1R2 L1R1 L1R0

0x13 L1ATRT L1AT3 L1AT2 L1AT1 L1AT0 L1RT3 L1RT2 L1RT1 L1RT0

0x14 L2AR L2A3 L2A2 L2A1 L2A0 L2R3 L2R2 L2R1 L2R0

0x15 L2ATRT L2AT3 L2AT2 L2AT1 L2AT0 L2RT3 L2RT2 L2RT1 L2RT0

0x16 CFADDR Reserved Reserved CFA5 CFA4 CFA3 CFA2 CFA1 CFA0

0x17 B1CF1 C1B23 C1B22 C1B21 C1B20 C1B19 C1B18 C1B17 C1B16

0x18 B1CF2 C1B15 C1B14 C1B13 C1B12 C1B11 C1B10 C1B9 C1B8

0x19 B1CF3 C1B7 C1B6 C1B5 C1B4 C1B3 C1B2 C1B1 C1B0

0x1A B2CF1 C2B23 C2B22 C2B21 C2B20 C2B19 C2B18 C2B17 C2B16

0x1B B2CF2 C2B15 C2B14 C2B13 C2B12 C2B11 C2B10 C2B9 C2B8

0x1C B2CF3 C2B7 C2B6 C2B5 C2B4 C2B3 C2B2 C2B1 C2B0

0x1D A1CF1 C3B23 C3B22 C3B21 C3B20 C3B19 C3B18 C3B17 C3B16

0x1E A1CF2 C3B15 C3B14 C3B13 C3B12 C3B11 C3B10 C3B9 C3B8

0x1F A1CF3 C3B7 C3B6 C3B5 C3B4 C3B3 C3B2 C3B1 C3B0

0x20 A2CF1 C4B23 C4B22 C4B21 C4B20 C4B19 C4B18 C4B17 C4B16

0x21 A2CF2 C4B15 C4B14 C4B13 C4B12 C4B11 C4B10 C4B9 C4B8

STA350BW Register description

Doc ID 018572 Rev 3 31/86

0x22 A2CF3 C4B7 C4B6 C4B5 C4B4 C4B3 C4B2 C4B1 C4B0

0x23 B0CF1 C5B23 C5B22 C5B21 C5B20 C5B19 C5B18 C5B17 C5B16

0x24 B0CF2 C5B15 C5B14 C5B13 C5B12 C5B11 C5B10 C5B9 C5B8

0x25 B0CF3 C5B7 C5B6 C5B5 C5B4 C5B3 C5B2 C5B1 C5B0

0x26 CFUD Reserved RA R1 WA W1

0x27 MPCC1 MPCC15 MPCC14 MPCC13 MPCC12 MPCC11 MPCC10 MPCC9 MPCC8

0x28 MPCC2 MPCC7 MPCC6 MPCC5 MPCC4 MPCC3 MPCC2 MPCC1 MPCC0

0x29 DCC1 DCC15 DCC14 DCC13 DCC12 DCC11 DCC10 DCC9 DCC8

0x2A DCC2 DCC7 DCC6 DCC5 DCC4 DCC3 DCC2 DCC1 DCC0

0x2B FDRC1 FDRC15 FDRC14 FDRC13 FDRC12 FDRC11 FDRC10 FDRC9 FDRC8

0x2C FDRC2 FDRC7 FDRC6 FDRC5 FDRC4 FDRC3 FDRC2 FDRC1 FDRC0

0x2D STATUS PLLUL FAULT UVFAULT OVFAULT OCFAULT OCWARN TFAULT TWARN

0x2E Reserved Reserved RO1BACT R5BACT R4BACT R3BACT R2BACT R1BACT

0x2F Reserved Reserved R01BEND R5BEND R4BEND R3BEND R2BEND R1BEND

0x30 Reserved Reserved R5BBAD R4BBAD R3BBAD R2BBAD R1BBAD

0x31 EQCFG XOB Reserved Reserved AMGC3 AMGC2 Reserved SEL1 SEL0

0x32 EATH1 EATHEN1 EATH1[6] EATH1[5] EATH1[4] EATH1[3] EATH1[2] EATH1[1] EATH1[0]

0x33 ERTH1 ERTHEN1 ERTH1[6] ERTH1[5] ERTH1[4] ERTH1[3] ERTH1[2] ERTH1[1] ERTH1[0]

0x34 EATH2 EATHEN2 EATH2[6] EATH2[5] EATH2[4] EATH2[3] EATH2[2] EATH2[1] EATH2[0]

0x35 ERTH2 ERTHEN2 ERTH2[6] ERTH2[5] ERTH2[4] ERTH2[3] ERTH2[2] ERTH2[1] ERTH2[0]

0x36 CONFX MDRC[1] MDRC[0] PS48DB XAR1 XAR2 BQ5 BQ6 BQ7

0x37 SVCA Reserved Reserved SVUPE SVUP[4] SVUP[3] SVUP[2] SVUP[1] SVUP[0]

0x38 SVCB Reserved Reserved SVDWE SVDW[4] SVDW[3] SVDW[2] SVDW[1] SVDW[0]

0x39 RMS0A R_C0[23] R_C0[22] R_C0[21] R_C0[20] R_C0[19] R_C0[18] R_C0[17] R_C0[16]

0x3A RMS0B R_C0[15] R_C0[14] R_C0[13] R_C0[12] R_C0[11] R_C0[10] R_C0[9] R_C0[8]

0x3B RMS0C R_C0[7] R_C0[6] R_C0[5] R_C0[4] R_C0[3] R_C0[2] R_C0[1] R_C0[0]

0x3C RMS1A R_C1[23] R_C1[22] R_C1[21] R_C1[20] R_C1[19] R_C1[18] R_C1[17] R_C1[16]

0x3D RMS1B R_C1[15] R_C1[14] R_C1[13] R_C1[12] R_C1[11] R_C1[10] R_C1[9] R_C1[8]

0x3E RMS1C R_C1[7] R_C1[6] R_C1[5] R_C1[4] R_C1[3] R_C1[2] R_C1[1] R_C1[0]

0x3F EVOLRES VRESEN VRESTG C3VR[1] C3VR[0] C2VR[1] C2VR[0] C1VR[1] C1VR[0]

0x40 Reserved

0x41 Reserved

0x42 Reserved

0x43 Reserved

0x44 Reserved

0x45 Reserved

0x46 Reserved

Table 7. Register summary (continued)

Addr Name D7 D6 D5 D4 D3 D2 D1 D0

32/86 Doc ID 018572 Rev 3

0x47 Reserved

0x48 NSHAPE NSHXEN NSHB7EN NSHB6EN NSHB5EN NSHB4EN NSHB3EN NSHB2EN NSHB1E

0x49 CXT[B4B1] CXTB4[1] CXTB4[0] CXTB3[1] CXTB3[0] CXTB2[1] CXTB2[0] CXTB1[1] CXTB1[0]

0x4A CXT[B7B5] Reserved Reserved CXTB7[1] CXTB7[0] CXTB6[1] CXTB6[0] CXTB5[1] CXTB5[0]

0x4B MISC1 RPDNEN NSHHPEN BRIDGOFF Reserved Reserved CPWMEN Reserved Reserved

0x4C MISC2 Reserved Reserved Reserved PNDLSL[2] PNDLSL[1] PNDLSL[0] Reserved Reserved

0x4D Reserved

0x4E Reserved

0x4F Reserved

0x50 Reserved

0x51 Reserved

0x52 Reserved

0x53 Reserved

0x54 Reserved

0x55 Reserved

0x56 Reserved

Table 7. Register summary (continued)

Addr Name D7 D6 D5 D4 D3 D2 D1 D0

STA350BW Register description

Doc ID 018572 Rev 3 33/86

7.1 Configuration register A (addr 0x00)

7.1.1 Master clock select

The STA350BW supports sample rates of 32 kHz, 44.1 kHz, 48 kHz, 88.2 kHz, 96 kHz,

176.4 kHz, and 192 kHz. Therefore the internal clock is:

●32.768 MHz for 32 kHz

●45.1584 MHz for 44.1 kHz, 88.2 kHz, and 176.4 kHz

●49.152 MHz for 48 kHz, 96 kHz, and 192 kHz

The external clock frequency provided to the XTI pin must be a multiple of the input sample

frequency (fs).

The relationship between the input clock and the input sample rate is determined by both

the MCSx and the IR (input rate) register bits. The MCSx bits determine the PLL factor

generating the internal clock and the IR bit determines the oversampling ratio used

internally.

D7 D6 D5 D4 D3 D2 D1 D0

FDRB TWAB TWRB IR1 IR0 MCS2 MCS1 MCS0

01100011

Table 8. Master clock select

Bit R/W RST Name Description

0R/W 1 MCS0

Selects the ratio between the input I2S sample

frequency and the input clock.

1R/W 1 MCS1

2R/W 0 MCS2

Table 9. Input sampling rates

Input sample rate

fs (kHz) IR MCS[2:0]

101 100 011 010 001 000

32, 44.1, 48 00 576 * fs 128 * fs 256 * fs 384 * fs 512 * fs 768 * fs

88.2, 96 01 NA 64 * fs 128 * fs 192 * fs 256 * fs 384 * fs

176.4, 192 1X NA 32 * fs 64 * fs 96 * fs 128 * fs 192 * fs

34/86 Doc ID 018572 Rev 3

7.1.2 Interpolation ratio select

The STA350BW has variable interpolation (oversampling) settings such that internal

processing and FFX output rates remain consistent. The first processing block interpolates

by either 2-times or 1-time (pass-through) or provides a 2-times downsample. The

oversampling ratio of this interpolation is determined by the IR bits.

7.1.3 Thermal warning recovery bypass

If the thermal warning adjustment is enabled (TWAB = 0), then the thermal warning

recovery determines if the -3 dB output limit is removed when thermal warning is negative.

If TWRB = 0 and TWAB = 0, then when a thermal warning disappears the -3 dB output limit

is removed and the gain is added back to the system. If TWRB = 1 and TWAB = 0, then

when a thermal warning disappears the -3 dB output limit remains until TWRB is changed to

zero or the device is reset.

7.1.4 Thermal warning adjustment bypass

Table 10. Internal interpolation ratio

Bit R/W RST Name Description

4:3 R/W 00 IR [1:0] Selects internal interpolation ratio based on input I2S

sample frequency

Table 11. IR bit settings as a function of input sample rate

Input sample rate fs (kHz) IR 1st stage interpolation ratio

32 00 2 times oversampling

44.1 00 2 times oversampling

48 00 2 times oversampling

88.2 01 Pass-through

96 01 Pass-through

176.4 10 2 times downsampling

192 10 2 times downsampling

Table 12. Thermal warning recovery bypass

Bit R/W RST Name Description

5R/W 1 TWRB 0: Thermal warning recovery enabled

1: Thermal warning recovery disabled

Table 13. Thermal warning adjustment bypass

Bit R/W RST Name Description

6R/W 1 TWAB 0: Thermal warning adjustment enabled

1: Thermal warning adjustment disabled

STA350BW Register description

Doc ID 018572 Rev 3 35/86

The on-chip STA350BW power output block provides feedback to the digital controller using

inputs to the power control block. Input TWARN is used to indicate a thermal warning

condition. When TWARN is asserted (set to 0) for a period of time greater than 400 ms, the

power control block forces a -3 dB output limit (determined by TWOCL in the coefficient

RAM) to the modulation limit in an attempt to eliminate the thermal warning condition. Once

the thermal warning output limit adjustment is applied, it remains in this state until reset,

unless FDRB = 0.

7.1.5 Fault detect recovery bypass

The on-chip STA350BW power output block provides feedback to the digital controller using

inputs to the power control block. The FAULT input is used to indicate a fault condition (either

over-current or thermal). When FAULT is asserted (set to 0), the power control block

attempts a recovery from the fault by asserting the tri-state output (setting it to 0 which

directs the power output block to begin recovery), holds it at 0 for period of time in the range

of 0.1 ms to 1 second as defined by the fault-detect recovery constant register (FDRC

registers 0x29-0x2A), then toggles it back to 1. This sequence is repeated as long as the

fault indication exists. This feature is enabled by default but can be bypassed by setting the

FDRB control bit to 1.

7.2 Configuration register B (addr 0x01)

7.2.1 Serial audio input interface format

Table 14. Fault detect recovery bypass

Bit R/W RST Name Description

7R/W 0 FDRB 0: fault detect recovery enabled

1: fault detect recovery disabled

D7 D6 D5 D4 D3 D2 D1 D0

C2IM C1IM DSCKE SAIFB SAI3 SAI2 SAI1 SAI0

10000000

Table 15. Serial audio input interface

Bit R/W RST Name Description

0 R/W 0 SAI0

Determines the interface format of the input serial

digital audio interface.

1 R/W 0 SAI1

2 R/W 0 SAI2

3 R/W 0 SAI3

36/86 Doc ID 018572 Rev 3

7.2.2 Serial data interface

The STA350BW audio serial input was designed to interface with standard digital audio

components and to accept a number of serial data formats. The STA350BW always acts as

the slave when receiving audio input from standard digital audio components. Serial data for

two channels is provided using three inputs: left/right clock LRCKI, serial clock BICKI, and

serial data 1 and 2 SDI12.

The SAI bits (D3 to D0) and the SAIFB bit (D4) are used to specify the serial data format.

The default serial data format is I2S, MSB-first. Available formats are shown in the tables

that follow.

7.2.3 Serial data first bit

Table 16. Serial data first bit

SAIFB Format

0 MSB-first

1 LSB-first

Table 17. Support serial audio input formats for MSB-first (SAIFB = 0)

BICKI SAI [3:0] SAIFB Interface format

32 * fs 0000 0 I2S 15-bit data

0001 0 Left/right-justified 16-bit data

48 * fs

0000 0 I2S 16 to 23-bit data

0001 0 Left-justified 16 to 24-bit data

0010 0 Right-justified 24-bit data

0110 0 Right-justified 20-bit data

1010 0 Right-justified 18-bit data

1110 0 Right-justified 16-bit data

64 * fs

0000 0 I2S 16 to 24-bit data

0001 0 Left-justified 16 to 24-bit data

0010 0 Right-justified 24-bit data

0110 0 Right-justified 20-bit data

1010 0 Right-justified 18-bit data

1110 0 Right-justified 16-bit data

STA350BW Register description

Doc ID 018572 Rev 3 37/86

To make the STA350BW work properly, the serial audio interface LRCKI clock must be

synchronous to the PLL output clock. It means that:

■the frequency of PLL clock / frequency of LRCKI = N ±4 cycles,

where N depends on the settings in Table 11 on page 34

■the PLL must be locked.

If these two conditions are not met, and the IDE bit (reg 0x05 bit 2) is set to 1, the

STA350BW will immediately mute the I2S PCM data out (provided to the processing block)

and it will freeze any active processing task.

Table 18. Supported serial audio input formats for LSB-first (SAIFB = 1)

BICKI SAI [3:0] SAIFB Interface format

32 * fs 1100 1 I2S 15-bit data

1110 1 Left/right-justified 16-bit data

48 * fs

0100 1 I2S 23-bit data

0100 1 I2S 20-bit data

1000 1 I2S 18-bit data

1100 1 LSB first I2S 16-bit data

0001 1 Left-justified 24-bit data

0101 1 Left-justified 20-bit data

1001 1 Left-justified 18-bit data

1101 1 Left-justified 16-bit data

0010 1 Right-justified 24-bit data

0110 1 Right-justified 20-bit data

1010 1 Right-justified 18-bit data

1110 1 Right-justified 16-bit data

64 * fs

0000 1 I2S 24-bit data

0100 1 I2S 20-bit data

1000 1 I2S 18-bit data

1100 1 LSB first I2S 16-bit data

0001 1 Left-justified 24-bit data

0101 1 Left-justified 20-bit data

1001 1 Left-justified 18-bit data

1101 1 Left-justified 16-bit data

0010 1 Right-justified 24-bit data

0110 1 Right-justified 20-bit data

1010 1 Right-justified 18-bit data

1110 1 Right-justified 16-bit data

38/86 Doc ID 018572 Rev 3

To avoid any audio side effects (like pop noise), it is strongly recommended to soft-mute any

audio streams flowing into the STA350BW data path before the desynchronization event

happens. At the same time any processing related to the I2C configuration should be issued

only after the serial audio interface and the internal PLL are synchronous again.

Note: Any mute or volume change causes some delay in the completion of the I2C operation due

to the soft-volume feature. The soft-volume phase change must be finished before any clock

desynchronization.

7.2.4 Delay serial clock enable

7.2.5 Channel input mapping

Each channel received via I2S can be mapped to any internal processing channel via the

Channel Input Mapping registers. This allows for flexibility in processing. The default

settings of these registers map each I2S input channel to its corresponding processing

channel.

Table 19. Delay serial clock enable

Bit R/W RST Name Description

5R/W 0 DSCKE

0: No serial clock delay

1: Serial clock delay by 1 core clock cycle to tolerate

anomalies in some I2S master devices

Table 20. Channel input mapping

Bit R/W RST Name Description

6R/W 0 C1IM 0: Processing channel 1 receives Left I2S Input

1: Processing channel 1 receives Right I2S Input

7R/W 1 C2IM 0: Processing channel 2 receives Left I2S Input

1: Processing channel 2 receives Right I2S Input

STA350BW Register description

Doc ID 018572 Rev 3 39/86

7.3 Configuration register C (addr 0x02)

7.3.1 FFX power output mode

The FFX power output mode selects how the FFX output timing is configured.

Different power devices use different output modes.

7.3.2 FFX compensating pulse size register

Table 6:

D7 D6 D5 D4 D3 D2 D1 D0

OCRB CSZ3 CSZ2 CSZ1 CSZ0 OM1 OM0

1 011111

Table 21. FFX power output mode

Bit R/W RST Name Description

0R/W 1 OM0 Selects configuration of FFX output.

1R/W 1 OM1

Table 22. Output modes

OM[1,0] Output stage mode

00 Drop compensation

01 Discrete output stage - tapered compensation

10 Full power mode

11 Variable drop compensation (CSZx bits)

Table 23. FFX compensating pulse size bits

Bit R/W RST Name Description

2R/W 1 CSZ0

When OM[1,0] = 11, this register determines the

size of the FFX compensating pulse from 0 clock

ticks to 15 clock ticks.

3R/W 1 CSZ1

4R/W 1 CSZ2

5R/W 0 CSZ3

Table 24. Compensating pulse size

CSZ[3:0] Compensating pulse size

0000 0 ns (0 tick) compensating pulse size

0001 20 ns (1 tick) clock period compensating pulse size

……

1111 300 ns (15 tick) clock period compensating pulse size

40/86 Doc ID 018572 Rev 3

7.3.3 Overcurrent warning detect adjustment bypass

The OCWARN input is used to indicate an overcurrent warning condition. When OCWARN

is asserted (set to 0), the power control block forces an adjustment to the modulation limit

(default is -3 dB) in an attempt to eliminate the overcurrent warning condition. Once the

overcurrent warning volume adjustment is applied, it remains in this state until a reset

occurs. The level of adjustment can be changed via the TWOCL (thermal warning/over

current limit) setting which is address 0x37 of the user-defined coefficient RAM.

7.4 Configuration register D (addr 0x03)

7.4.1 High-pass filter bypass

The STA350BW features an internal digital high-pass filter for the purpose of AC coupling.

The purpose of this filter is to prevent DC signals from passing through an FFX amplifier. DC

signals can cause speaker damage. When HPB = 0, this filter is enabled.

7.4.2 De-emphasis

Table 25. Overcurrent warning bypass

Bit R/W RST Name Description

7 R/W 1 OCRB 0: Overcurrent warning adjustment enabled

1: Overcurrent warning adjustment disabled

D7 D6 D5 D4 D3 D2 D1 D0

SME ZDE DRC BQL PSL DSPB DEMP HPB

01000000

Table 26. High-pass filter bypass

Bit R/W RST Name Description

0R/W 0 HPB Setting of one bypasses internal AC coupling digital

high-pass filter

Table 27. De-emphasis

Bit R/W RST Name Description

1R/W 0 DEMP 0: No de-emphasis

1: Enable de-emphasis on all channels

STA350BW Register description

Doc ID 018572 Rev 3 41/86

7.4.3 DSP bypass

Setting the DSPB bit to 1 bypasses the EQ function of the STA350BW.

7.4.4 Post-scale link

Post-scale functionality can be used for power-supply error correction. For multi-channel

applications running off the same power-supply, the post-scale values can be linked to the

value of channel 1 for ease of use and to update the values faster.

7.4.5 Biquad coefficient link

For ease of use, all channels can use the biquad coefficients loaded into the Channel-1

coefficient RAM space by setting the BQL bit to 1. Therefore, any EQ updates only have to

be performed once.

7.4.6 Dynamic range compression/anti-clipping bit

Both limiters can be used in one of two ways, anti-clipping or dynamic range compression.

When used in anti-clipping mode the limiter threshold values are constant and dependent on

the limiter settings. In dynamic range compression mode the limiter threshold values vary

with the volume settings allowing a nighttime listening mode that provides a reduction in the

dynamic range regardless of the volume level.

Table 28. DSP bypass

Bit R/W RST Name Description

2 R/W 0 DSPB 0: Normal operation

1: Bypass of biquad and bass/treble functions

Table 29. Post-scale link

Bit R/W RST Name Description

3 R/W 0 PSL 0: Each channel uses individual post-scale value

1: Each channel uses channel 1 post-scale value

Table 30. Biquad coefficient link

Bit R/W RST Name Description

4R/W 0 BQL 0: Each channel uses coefficient values

1: Each channel uses channel 1 coefficient values

Table 31. Dynamic range compression/anti-clipping bit

Bit R/W RST Name Description

5 R/W 0 DRC 0: Limiters act in anti-clipping mode

1: Limiters act in dynamic range compression mode

42/86 Doc ID 018572 Rev 3

7.4.7 Zero-detect mute enable

Setting the ZDE bit enables the zero-detect automatic mute. The zero-detect circuit looks at

the data for each processing channel at the output of the crossover (bass management)

filter. If any channel receives 2048 consecutive zero value samples (regardless of fs) then

that individual channel is muted if this function is enabled.

7.4.8 Submix mode enable

7.5 Configuration register E (addr 0x04)

7.5.1 Max power correction variable

7.5.2 Max power correction

Setting the MPC bit turns on special processing that corrects the STA350BW power device

at high power. This mode should lower the THD+N of a full FFX system at maximum power

output and slightly below. If enabled, MPC is operational in all output modes except tapered

(OM[1,0] = 01) and binary. When OCFG = 00, MPC will not effect channels 3 and 4, the line-

out channels.

Table 32. Zero-detect mute enable

Bit R/W RST Name Description

6 R/W 1 ZDE Setting of 1 enables the automatic zero-detect mute

Table 33. Submix mode enable

Bit R/W RST Name Description

7R/W 0 SME 0: Sub Mix into Left/Right disabled

1: Sub Mix into Left/Right enabled

D7 D6 D5 D4 D3 D2 D1 D0

SVE ZCE DCCV PWMS AME NSBW MPC MPCV

11000010

Table 34. Max power correction variable

Bit R/W RST Name Description

0R/W 0 MPCV 0: Use standard MPC coefficient

1: Use MPCC bits for MPC coefficient

Table 35. Max power correction

Bit R/W RST Name Description

1R/W 1 MPC Setting of 1 enables power bridge correction for THD

reduction near maximum power output.

STA350BW Register description

Doc ID 018572 Rev 3 43/86

7.5.3 Noise-shaper bandwidth selection

7.5.4 AM mode enable

The STA350BW features an FFX processing mode that minimizes the amount of noise

generated in the frequency range of AM radio. This mode is intended for use when FFX is

operating in a device with an AM tuner active. The SNR of the FFX processing is reduced to

approximately 83 dB in this mode, which is still greater than the SNR of AM radio.

7.5.5 PWM speed mode

7.5.6 Distortion compensation variable enable

7.5.7 Zero-crossing volume enable

The ZCE bit enables zero-crossing volume adjustments. When volume is adjusted on digital

zero-crossings, no clicks are audible.

Table 36. Noise-shaper bandwidth selection

Bit R/W RST Name Description

2 R/W 0 NSBW 1: Third order NS

0: Fourth order NS

Table 37. AM mode enable

Bit R/W RST Name Description

3R/W 0 AME 0: Normal FFX operation

1: AM reduction mode FFX operation

Table 38. PWM speed mode

Bit R/W RST Name Description

4R/W 0 PWMS 0: Normal speed (384 kHz) all channels

1: Odd speed (341.3 kHz) all channels

Table 39. Distortion compensation variable enable

Bit R/W RST Name Description

5R/W 0 DCCV 0: Use preset DC coefficient

1: Use DCC coefficient

Table 40. Zero-crossing volume enable

Bit R/W RST Name Description

6R/W 1 ZCE 1: Volume adjustments only occur at digital zero-crossings

0: Volume adjustments occur immediately

44/86 Doc ID 018572 Rev 3

7.5.8 Soft-volume update enable

7.6 Configuration register F (addr 0x05)

7.6.1 Output configuration

Note: To the left of the arrow is the processing channel. When using channel output mapping, any

of the three processing channel outputs can be used for any of the three inputs.

Table 41. Soft-volume update enable

Bit R/W RST Name Description

7R/W 1 SVE 1: Volume adjustments ramp according to SVR settings

0: Volume adjustments occur immediately

D7 D6 D5 D4 D3 D2 D1 D0

EAPD PWDN ECLE LDTE BCLE IDE OCFG1 OCFG0

01011100

Table 42. Output configuration

Bit R/W RST Name Description

0 R/W 0 OCFG0 Selects the output configuration

1 R/W 0 OCFG1

Table 43. Output configuration engine selection

OCFG[1:0] Output configuration Config pin

2-channel (full-bridge) power, 2-channel data-out:

1A/1B → 1A/1B

2A/2B → 2A/2B

LineOut1 → 3A/3B

LineOut2 → 4A/4B

Line Out Configuration determined by LOC register

2(half-bridge).1(full-bridge) on-board power:

1A → 1A Binary 0 °

2A → 1B Binary 90°

3A/3B → 2A/2B Binary 45°

1A/B → 3A/B Binary 0°

2A/B → 4A/B Binary 90°

2 Channel (Full-Bridge) Power, 1 Channel FFX:

1A/1B → 1A/1B

2A/2B → 2A/2B

3A/3B → 3A/3B

EAPDEXT and TWARNEXT Active

1 Channel Mono-Parallel:

3A → 1A/1B w/ C3BO 45°

3B → 2A/2B w/ C3BO 45°

1A/1B → 3A/3B

2A/2B → 4A/4B

STA350BW Register description

Doc ID 018572 Rev 3 45/86

Figure 20. OCFG = 00 (default value)

Figure 21. OCFG = 01

Figure 22. OCFG = 10

Half

Bridge

Half

Bridge

Half

Bridge

Half

Bridge

OUT1A

OUT1B

OUT2A

OUT2B

Channel 2

Channel 1

LPF

LineOut1

OUT3B

LPF

LineOut2

OUT4B

OUT4A

OUT3A

Half

Bridge

Half

Bridge

Half

Bridge

Half

Bridge

OUT1A

OUT1B

OUT2A

OUT2B

Channel 2

Channel 1

LPF

LineOut1

OUT3B

LPF

LineOut2

OUT4B

OUT4A

OUT3A

AM045185v1

Half

Bridge

Half

Bridge

Half

Bridge

Half

Bridge

OUT1A

OUT1B

OUT2A

OUT2B

Channel 3

Channel 1

Channel 2

Half

Bridge

Half

Bridge

Half

Bridge

Half

Bridge

OUT1A

OUT1B

OUT2A

OUT2B

Channel 3

Channel 1

Channel 2

AM045186v1

Half

Bridge

Half

Bridge

Half

Bridge

Half

Bridge

OUT1A

OUT1B

OUT2A

OUT2B

Channel 2

Channel 1

Power

Device

OUT3B

OUT3A

EAPD

Channel 3

Half

Bridge

Half

Bridge

Half

Bridge

Half

Bridge

OUT1A

OUT1B

OUT2A

OUT2B

Channel 2

Channel 1

Power

Device

OUT3B

OUT3A

EAPD

Channel 3

AM045187v1

46/86 Doc ID 018572 Rev 3

Figure 23. OCFG = 11

The STA350BW can be configured to support different output configurations. For each PWM

output channel a PWM slot is defined. A PWM slot is always 1 / (8 * fs) seconds length. The

PWM slot defines the maximum extension for the PWM rising and falling edge, that is, the

rising edge as well as the falling edge cannot range outside the PWM slot boundaries.

Figure 24. Output mapping scheme

For each configuration the PWM signals from the digital driver are mapped in different ways

to the power stage.

Half

Bridge

Half

Bridge

Half

Bridge

Half

Bridge

OUT1A

OUT1B

OUT2A

OUT2B

Channel 3

OUT3B

OUT4B

OUT4A

OUT3AChannel 1

Channel 2

Half

Bridge

Half

Bridge

Half

Bridge

Half

Bridge

OUT1A

OUT1B

OUT2A

OUT2B

Channel 3

OUT3B

OUT4B

OUT4A

OUT3AChannel 1

Channel 2

AM045188v1

FFX ™

modulator

REMAP

FFX1A

FFX1 B

FFX2 A

FFX 2B

OUT1A

OUT1B

OUT2A

OUT2B

Power

Bridge

OUT1A

OUT1B

OUT2A

OUT2B

FFX3A

FFX3B

FFX4 A

FFX 4B

OUT3A

OUT3B

OUT4A

OUT4B

FFX ™

modulator

REMAP

Power

Bridge

FFX ™

modulator

REMAP

Power

Bridge

FFX ™

modulator

REMAP

Power

Bridge

FFX ™

modulator

REMAP

Power

Bridge

FFX ™

modulator

REMAP

Power

Bridge

AM045189v1

STA350BW Register description

Doc ID 018572 Rev 3 47/86

2.0 channels, two full bridges (OCFG = 00)

●FFX1A -> OUT1A

●FFX1B -> OUT1B

●FFX2A -> OUT2A

●FFX2B -> OUT2B

●FFX3A -> OUT3A

●FFX3B -> OUT3B

●FFX4A -> OUT4A

●FFX4B -> OUT4B

●FFX1A/1B configured as ternary

●FFX2A/2B configured as ternary

●FFX3A/3B configured as lineout ternary

●FFX4A/4B configured as lineout ternary

On channel 3 line out (LOC bits = 00) the same data as channel 1 processing is sent. On

channel 4 line out (LOC bits = 00) the same data as channel 2 processing is sent. In this

configuration, neither volume control nor EQ has any effect on channels 3 and 4.

In this configuration the PWM slot phase is the following as shown in Figure 25.

Figure 25. 2.0 channels (OCFG = 00) PWM slots

OUT1A

OUT1B

OUT2A

OUT2B

OUT3A

OUT3B

OUT4A

OUT4B

OUT1A

OUT1B

OUT2A

OUT2B

OUT3A

OUT3B

OUT4A

OUT4B

AM045190v1

48/86 Doc ID 018572 Rev 3

2.1 channels, two half-bridges + one full-bridge (OCFG = 01)

●FFX1A -> OUT1A

●FFX2A -> OUT1B

●FFX3A -> OUT2A

●FFX3B -> OUT2B

●FFX1A -> OUT3A

●FFX1B -> OUT3B

●FFX2A -> OUT4A

●FFX2B -> OUT4B

●FFX1A/1B configured as binary

●FFX2A/2B configured as binary

●FFX3A/3B configured as binary

●FFX4A/4B is not used

In this configuration, channel 3 has full control (volume, EQ, etc…). On OUT3/OUT4

channels the channel 1 and channel 2 PWM are replicated.

In this configuration the PWM slot phase is the following as shown in Figure 26.

Figure 26. 2.1 channels (OCFG = 01) PWM slots

OUT1A

OUT2A

OUT2B

OUT3A

OUT3B

OUT1B

OUT4A

OUT4B

OUT1A

OUT2A

OUT2B

OUT3A

OUT3B

OUT1B

OUT4A

OUT4B

OUT1A

OUT2A

OUT2B

OUT3A

OUT3B

OUT1B

OUT4A

OUT4B

OUT1A

OUT2A

OUT2B

OUT3A

OUT3B

OUT1B

OUT1A

OUT2A

OUT2B

OUT3A

OUT3B

OUT1B

OUT4A

OUT4B

OUT1A

OUT2A

OUT2B

OUT3A

OUT3B

OUT1B

OUT4A

OUT4B

AM045191v1

STA350BW Register description

Doc ID 018572 Rev 3 49/86

2.1 channels, two full-bridge + one external full-bridge (OCFG = 10)

●FFX1A -> OUT1A

●FFX1B -> OUT1B

●FFX2A -> OUT2A

●FFX2B -> OUT2B

●FFX3A -> OUT3A

●FFX3B -> OUT3B

●EAPD -> OUT4A

●TWARN -> OUT4B

●FFX1A/1B configured as ternary

●FFX2A/2B configured as ternary

●FFX3A/3B configured as ternary

●FFX4A/4B is not used

In this configuration, channel 3 has full control (volume, EQ, etc…). On OUT4 channel the

external bridge control signals are muxed.

In this configuration the PWM slot phase is the following as shown in Figure 27.

Figure 27. 2.1 channels (OCFG = 10) PWM slots

OUT1A

OUT1B

OUT2A

OUT2B

OUT3A

OUT3B

OUT1A

OUT1B

OUT2A

OUT2B

OUT3A

OUT3B

OUT1A

OUT1B

OUT2A

OUT2B

OUT3A

OUT3B

OUT1A

OUT1B

OUT2A

OUT2B

OUT3A

OUT3B

AM045192v1

50/86 Doc ID 018572 Rev 3

7.6.2 Invalid input detect mute enable

Setting the IDE bit enables this function, which looks at the input I2S data and automatically

mutes if the signals are perceived as invalid.

7.6.3 Binary output mode clock loss detection

The BCLE bit detects loss of input MCLK in binary mode and will output 50% duty cycle.

7.6.4 LRCK double trigger protection

The LDTE bit actively prevents double triggering of the LRCLK.

7.6.5 Auto EAPD on clock loss

When active, the ECLE bit issues a power device power-down signal (EAPD) on clock loss

detection.

7.6.6 IC power-down

The PWDN register is used to place the IC in a low-power state. When PWDN is written

as 0, the output begins a soft-mute. After the mute condition is reached, EAPD is asserted

Table 44. Invalid input detect mute enable

Bit R/W RST Name Description

2 R/W 1 IDE Setting of 1 enables the automatic invalid input detect mute

Table 45. Binary output mode clock loss detection

Bit R/W RST Name Description

3 R/W 1 BCLE Binary output mode clock loss detection enable

Table 46. LRCK double trigger protection

Bit R/W RST Name Description

4 R/W 1 LDTE LRCLK double trigger protection enable

Table 47. Auto EAPD on clock loss

Bit R/W RST Name Description

5 R/W 0 ECLE Auto EAPD on clock loss

Table 48. IC power-down

Bit R/W RST Name Description

7R/W 1 PWDN 0: IC power-down low-power condition

1: IC normal operation

STA350BW Register description

Doc ID 018572 Rev 3 51/86

to power down the power-stage, then the master clock to all internal hardware except the

I2C block is gated. This places the IC in a very low power consumption state.

7.6.7 External amplifier power-down

The EAPD register directly disables/enables the internal power circuitry.

When EAPD = 0, the internal power section is placed in a low-power state (disabled). This

7.7 Volume control registers (addr 0x06 - 0x0A)

7.7.1 Mute/line output configuration register

Line output is only active when OCFG = 00. In this case LOC determines the line output

configuration. The source of the line output is always the channel 1 and 2 inputs.

7.7.2 Master volume register

7.7.3 Channel 1 volume

Table 49. External amplifier power-down

Bit R/W RST Name Description

7 R/W 0 EAPD 0: External power stage power down active

1: Normal operation

D7 D6 D5 D4 D3 D2 D1 D0

LOC1 LOC0 Reserved Reserved C3M C2M C1M MMUTE

00000000

Table 50. Line output configuration

LOC[1:0] Line output configuration

00 Line output fixed - no volume, no EQ

01 Line output variable - CH3 volume effects line output, no EQ

10 Line output variable with EQ - CH3 volume effects line output

D7 D6 D5 D4 D3 D2 D1 D0

MV7 MV6 MV5 MV4 MV3 MV2 MV1 MV0

11111111

D7 D6 D5 D4 D3 D2 D1 D0

C1V7 C1V6 C1V5 C1V4 C1V3 C1V2 C1V1 C1V0

01100000

52/86 Doc ID 018572 Rev 3

7.7.4 Channel 2 volume

7.7.5 Channel 3 / line output volume

The volume structure of the STA350BW consists of individual volume registers for each

channel and a master volume register that provides an offset to each channels volume

setting. The individual channel volumes are adjustable in 0.5 dB steps from +48 dB

to -80 dB.

As an example if C3V = 0x00 or +48 dB and MV = 0x18 or -12 dB, then the total gain for

channel 3 = +36 dB.

The master mute, when set to 1, mutes all channels at once, whereas the individual channel

mute (CxM) mutes only that channel. Both the master mute and the channel mutes provide

a “soft mute” with the volume ramping down to mute in 4096 samples from the maximum

volume setting at the internal processing rate (approximately 96 kHz).

A “hard (instantaneous) mute” can be obtained by programming a value of 0xFF (255) to

any channel volume register or the master volume register. When volume offsets are

provided via the master volume register, any channel whose total volume is less than -80 dB

is muted.

All changes in volume take place at zero-crossings when ZCE = 1 (Configuration register E

(addr 0x04)) on a per channel basis as this creates the smoothest possible volume

transitions. When ZCE = 0, volume updates occur immediately.

D7 D6 D5 D4 D3 D2 D1 D0

C2V7 C2V6 C2V5 C2V4 C2V3 C2V2 C2V1 C2V0

01100000

D7 D6 D5 D4 D3 D2 D1 D0

C3V7 C3V6 C3V5 C3V4 C3V3 C3V2 C3V1 C3V0

01100000

Table 51. Master volume offset as a function of MV[7:0]

MV[7:0] Volume offset from channel value

00000000 (0x00) 0 dB

00000001 (0x01) -0.5 dB

00000010 (0x02) -1 dB

……

01001100 (0x4C) -38 dB

……

11111110 (0xFE) -127.5 dB

11111111 (0xFF) Hard master mute

STA350BW Register description

Doc ID 018572 Rev 3 53/86

7.8 Audio preset registers (addr 0x0B and 0x0C)

7.8.1 Audio preset register 1 (addr 0x0B)

Using AMGC[3:0] bits, attack and release thresholds and rates are automatically configured

to properly fit application specific configurations. AMGC[3:2] is defined in register EQ

coefficients and DRC configuration register (addr 0x31) on page 71.

The AMGC[1:0] bits behave in two different ways depending on the value of AMGC[3:2].

When this value is 00, then bits AMGC[1:0] are defined below in Ta bl e 5 3.

Table 52. Channel volume as a function of CxV[7:0]

CxV[7:0] Volume

00000000 (0x00) +48 dB

00000001 (0x01) +47.5 dB

00000010 (0x02) +47 dB

……

01011111 (0x5F) +0.5 dB

01100000 (0x60) 0 dB

01100001 (0x61) -0.5 dB

……

11010111 (0xD7) -59.5 dB

11011000 (0xD8) -60 dB

11011001 (0xD9) -61 dB

11011010 (0xDA) -62 dB

……

11101100 (0xEC) -80 dB

11101101 (0xED) Hard channel mute

……

11111111 (0xFF) Hard channel mute

D7 D6 D5 D4 D3 D2 D1 D0

Reserved Reserved AMGC[1] AMGC[0] Reserved Reserved Reserved Reserved

00000000

Table 53. Audio preset gain compression/limiters selection for AMGC[3:2] = 00

AMGC[1:0] Mode

00 User-programmable GC

01 AC no clipping 2.1

10 AC limited clipping (10%) 2.1

11 DRC nighttime listening mode 2.1

54/86 Doc ID 018572 Rev 3

7.8.2 Audio preset register 2 (addr 0x0C)

7.8.3 AM interference frequency switching

7.8.4 Bass management crossover

D7 D6 D5 D4 D3 D2 D1 D0

XO3 XO2 XO1 XO0 AMAM2 AMAM1 AMAM0 AMAME

00000000

Table 54. AM interference frequency switching bits

Bit R/W RST Name Description

0 R/W 0 AMAME

Audio preset AM enable

0: switching frequency determined by PWMS setting

1: switching frequency determined by AMAM settings

Table 55. Audio preset AM switching frequency selection

AMAM[2:0] 48 kHz/96 kHz input fs 44.1 kHz/88.2 kHz input fs

000 0.535 MHz - 0.720 MHz 0.535 MHz - 0.670 MHz

001 0.721 MHz - 0.900 MHz 0.671 MHz - 0.800 MHz

010 0.901 MHz - 1.100 MHz 0.801 MHz - 1.000 MHz

011 1.101 MHz - 1.300 MHz 1.001 MHz - 1.180 MHz

100 1.301 MHz - 1.480 MHz 1.181 MHz - 1.340 MHz

101 1.481 MHz - 1.600 MHz 1.341 MHz - 1.500 MHz

110 1.601 MHz - 1.700 MHz 1.501 MHz - 1.700 MHz

Table 56. Bass management crossover

Bit R/W RST Name Description

4R/W 0 XO0

Selects the bass-management crossover frequency.

A 1st-order hign-pass filter (channels 1 and 2) or a

2nd-order low-pass filter (channel 3) at the selected

frequency is performed.

5R/W 0 XO1

6R/W 0 XO2

7R/W 0 XO3

Table 57. Bass management crossover frequency

XO[3:0] Crossover frequency

0000 User-defined

0001 80 Hz

0010 100 Hz

0011 120 Hz

STA350BW Register description

Doc ID 018572 Rev 3 55/86

7.9 Channel configuration registers (addr 0x0E - 0x10)

7.9.1 Tone control bypass

Tone control (bass/treble) can be bypassed on a per-channel basis for channels 1 and 2.

7.9.2 EQ bypass

EQ control can be bypassed on a per-channel basis for channels 1 and 2. If EQ control is

bypassed on a given channel, the prescale and all filters (high-pass, biquads, de-emphasis,

bass, treble in any combination) are bypassed for that channel.

0100 140 Hz

0101 160 Hz

0110 180 Hz

0111 200 Hz

1000 220 Hz

1001 240 Hz

1010 260 Hz

1011 280 Hz

1100 300 Hz

1101 320 Hz

1110 340 Hz

1111 360 Hz

Table 57. Bass management crossover frequency (continued)

XO[3:0] Crossover frequency

D7 D6 D5 D4 D3 D2 D1 D0

C1OM1 C1OM0 C1LS1 C1LS0 C1BO C1VPB C1EQBP C1TCB

00000000

D7 D6 D5 D4 D3 D2 D1 D0

C2OM1 C2OM0 C2LS1 C2LS0 C2BO C2VPB C2EQBP C2TCB

01000000

D7 D6 D5 D4 D3 D2 D1 D0

C3OM1 C3OM0 C3LS1 C3LS0 C3BO C3VPB Reserved Reserved

10000000

Table 58. Tone control bypass

CxTCB Mode

0 Perform tone control on channel x - normal operation

1 Bypass tone control on channel x

56/86 Doc ID 018572 Rev 3

7.9.3 Volume bypass

Each channel contains an individual channel volume bypass. If a particular channel has

volume bypassed via the CxVBP = 1 register then only the channel volume setting for that

particular channel affects the volume setting, the master volume setting will not affect that

channel.

7.9.4 Binary output enable registers

Each individual channel output can be set to output a binary PWM stream. In this mode

output A of a channel is considered the positive output and output B is the negative inverse.

7.9.5 Limiter select

Limiter selection can be made on a per-channel basis according to the channel limiter select

bits.

7.9.6 Output mapping

Output mapping can be performed on a per channel basis according to the CxOM channel

output mapping bits. Each input into the output configuration engine can receive data from

any of the three processing channel outputs.

Table 59. EQ bypass

CxEQBP Mode

0 Perform EQ on channel x - normal operation

1 Bypass EQ on channel x

Table 60. Binary output enable registers

CxBO Mode

0 FFX 3-state output - normal operation

1 Binary output

Table 61. Channel limiter mapping as a function of CxLS bits

CxLS[1:0] Channel limiter mapping

00 Channel has limiting disabled

01 Channel is mapped to limiter #1

10 Channel is mapped to limiter #2

Table 62. Channel output mapping as a function of CxOM bits

CxOM[1:0] Channel x output source from

00 Channel1

01 Channel 2

10 Channel 3

STA350BW Register description

Doc ID 018572 Rev 3 57/86

7.10 Tone control register (addr 0x11)

7.10.1 Tone control

7.11 Dynamic control registers (addr 0x12 - 0x15)

7.11.1 Limiter 1 attack/release rate

7.11.2 Limiter 1 attack/release threshold

7.11.3 Limiter 2 attack/release rate

D7 D6 D5 D4 D3 D2 D1 D0

TTC3 TTC2 TTC1 TTC0 BTC3 BTC2 BTC1 BTC0

01110111

Table 63. Tone control boost/cut as a function of BTC and TTC bits

BTC[3:0]/TTC[3:0] Boost/Cut

0000 -12 dB

0001 -12 dB

……

0111 -4 dB

0110 -2 dB

0111 0 dB

1000 +2 dB

1001 +4 dB

……

1101 +12 dB

1110 +12 dB

1111 +12 dB

D7 D6 D5 D4 D3 D2 D1 D0

L1A3 L1A2 L1A1 L1A0 L1R3 L1R2 L1R1 L1R0

01101010

D7 D6 D5 D4 D3 D2 D1 D0

L1AT3 L1AT2 L1AT1 L1AT0 L1RT3 L1RT2 L1RT1 L1RT0

01101001

D7 D6 D5 D4 D3 D2 D1 D0

L2A3 L2A2 L2A1 L2A0 L2R3 L2R2 L2R1 L2R0

01101010

58/86 Doc ID 018572 Rev 3

7.11.4 Limiter 2 attack/release threshold

The STA350BW includes two independent limiter blocks. The purpose of the limiters is to

automatically reduce the dynamic range of a recording to prevent the outputs from clipping

in anti-clipping mode or to actively reduce the dynamic range for a better listening

environment such as a night-time listening mode which is often needed for DVDs. The two

modes are selected via the DRC bit in Configuration register E (addr 0x04) on page 42.

Each channel can be mapped to either limiter or not mapped, meaning that the channel will

clip when 0 dBfs is exceeded. Each limiter looks at the present value of each channel that is

mapped to it, selects the maximum absolute value of all these channels, performs the

limiting algorithm on that value, and then if needed adjusts the gain of the mapped channels

in unison.

The limiter attack thresholds are determined by the LxAT registers if EATHx[7] bits are set

to 0 else the thresholds are determined by EATHx[6:0] . It is recommended in anti-clipping

mode to set this to 0 dBfs, which corresponds to the maximum unclipped output power of an

FFX amplifier. Since gain can be added digitally within the STA350BW, it is possible to

exceed 0 dBfs or any other LxAT setting. When this occurs, the limiter, when active,

automatically starts reducing the gain. The rate at which the gain is reduced when the attack

threshold is exceeded is dependent upon the attack rate register setting for that limiter. Gain

reduction occurs on a peak-detect algorithm. Setting the EATHx[7] bits to 1 selects the

anti-clipping mode.

The limiter release thresholds are determined by the LxRT registers if ERTHx[7] bits are set

to 0, else the thresholds are determined by ERTHx[6:0]. Setting the ERTHx[7] bits to 1

automatically selects the anti-clipping mode. The release of the limiter, when the gain is

again increased, is dependent on an RMS-detect algorithm. The output of the volume/limiter

block is passed through an RMS filter. The output of this filter is compared to the release

threshold, determined by the Release Threshold register. When the RMS filter output falls

below the release threshold, the gain is again increased at a rate dependent upon the

Release Rate register. The gain can never be increased past its set value and, therefore, the

release only occurs if the limiter has already reduced the gain. The release threshold value

can be used to set what is effectively a minimum dynamic range, this is helpful as

overlimiting can reduce the dynamic range to virtually zero and cause program material to

sound “lifeless”.

In AC mode, the attack and release thresholds are set relative to full-scale. In DRC mode,

the attack threshold is set relative to the maximum volume setting of the channels mapped

to that limiter and the release threshold is set relative to the maximum volume setting plus

the attack threshold.

D7 D6 D5 D4 D3 D2 D1 D0

L2AT3 L2AT2 L2AT1 L2AT0 L2RT3 L2RT2 L2RT1 L2RT0

01101001

STA350BW Register description

Doc ID 018572 Rev 3 59/86

Figure 28. Basic limiter and volume flow diagram

ATTENUATION SATURATION

RMS

LIMITER

GAIN

GAIN /VOLUME

INPUT OUTPUT

ATTENUATION SATURATION

RMS

LIMITER

GAIN

GAIN /VOLUME

INPUT OUTPUT

AM045193v1

Table 64. Limiter attack rate as a function

of LxA bits

Table 65. Limiter release rate as a

function of LxR bits

LxA[3:0] Attack rate dB/ms LxR[3:0] Release rate dB/ms

0000 3.1584

Fast

Slow

0000 0.5116

Fast

Slow

0001 2.7072 0001 0.1370

0010 2.2560 0010 0.0744

0011 1.8048 0011 0.0499

0100 1.3536 0100 0.0360

0101 0.9024 0101 0.0299

0110 0.4512 0110 0.0264

0111 0.2256 0111 0.0208

1000 0.1504 1000 0.0198

1001 0.1123 1001 0.0172

1010 0.0902 1010 0.0147

1011 0.0752 1011 0.0137

1100 0.0645 1100 0.0134

1101 0.0564 1101 0.0117

1110 0.0501 1110 0.0110

1111 0.0451 1111 0.0104

60/86 Doc ID 018572 Rev 3

Anti-clipping mode

Table 66. Limiter attack threshold as a

function of LxAT bits (AC-mode)

Table 67. Limiter release threshold as a

function of LxRT bits (AC-

mode)

LxAT[3:0] AC (dB relative to fs) LxRT[3:0] AC (dB relative to fs)

0000 -12 0000 -∞

0001 -10 0001 -29 dB

0010 -8 0010 -20 dB

0011 -6 0011 -16 dB

0100 -4 0100 -14 dB

0101 -2 0101 -12 dB

0110 0 0110 -10 dB

0111 +2 0111 -8 dB

1000 +3 1000 -7 dB

1001 +4 1001 -6 dB

1010 +5 1010 -5 dB

1011 +6 1011 -4 dB

1100 +7 1100 -3 dB

1101 +8 1101 -2 dB

1110 +9 1110 -1 dB

1111 +10 1111 -0 dB

STA350BW Register description

Doc ID 018572 Rev 3 61/86

Dynamic range compression mode

7.11.5 Limiter 1 extended attack threshold (addr 0x32)

The extended attack threshold value is determined as follows:

attack threshold = -12 + EATH1 / 4

7.11.6 Limiter 1 extended release threshold (addr 0x33)

The extended release threshold value is determined as follows:

release threshold = -12 + ERTH1 / 4

Table 68. Limiter attack threshold as a

function of LxAT bits (DRC -

mode)

Table 69. Limiter release threshold as a

as a function of LxRT bits

(DRC-mode)

LxAT[3:0] DRC (dB relative to Volume) LxRT[3:0] DRC (db relative to Volume +

LxAT)

0000 -31 0000 -∞

0001 -29 0001 -38 dB

0010 -27 0010 -36 dB

0011 -25 0011 -33 dB

0100 -23 0100 -31 dB

0101 -21 0101 -30 dB

0110 -19 0110 -28 dB

0111 -17 0111 -26 dB

1000 -16 1000 -24 dB

1001 -15 1001 -22 dB

1010 -14 1010 -20 dB

1011 -13 1011 -18 dB

1100 -12 1100 -15 dB

1101 -10 1101 -12 dB

1110 -7 1110 -9 dB

1111 -4 1111 -6 dB

D7 D6 D5 D4 D3 D2 D1 D0

EATHEN1 EATH1[6] EATH1[5] EATH1[4] EATH1[3] EATH1[2] EATH1[1] EATH1[0]

TBDTBDTBDTBDTBDTBDTBDTBD

D7 D6 D5 D4 D3 D2 D1 D0

ERTHEN1 ERTH1[6] ERTH1[5] ERTH1[4] ERTH1[3] ERTH1[2] ERTH1[1] ERTH1[0]

TBDTBDTBDTBDTBDTBDTBDTBD

62/86 Doc ID 018572 Rev 3

7.11.7 Limiter 2 extended attack threshold (addr 0x34)

The extended attack threshold value is determined as follows:

attack threshold = -12 + EATH2 / 4

7.11.8 Limiter 2 extended release threshold (addr 0x35)

The extended release threshold value is determined as follows:

release threshold = -12 + ERTH2 / 4

Note: Attack/release threshold step is 0.125 dB in the range -12 dB to 0 dB.

7.12 User-defined coefficient control registers (addr 0x16 - 0x26)

7.12.1 Coefficient address register

7.12.2 Coefficient b1 data register bits 23:16

7.12.3 Coefficient b1 data register bits 15:8

7.12.4 Coefficient b1 data register bits 7:0

D7 D6 D5 D4 D3 D2 D1 D0

EATHEN2 EATH2[6] EATH2[5] EATH2[4] EATH2[3] EATH2[2] EATH2[1] EATH2[0]

TBDTBDTBDTBDTBDTBDTBDTBD

D7 D6 D5 D4 D3 D2 D1 D0

ERTHEN2 ERTH2[6] ERTH2[5] ERTH2[4] ERTH2[3] ERTH2[2] ERTH2[1] ERTH2[0]

TBDTBDTBDTBDTBDTBDTBDTBD

D7 D6 D5 D4 D3 D2 D1 D0

CFA5 CFA4 CFA3 CFA2 CFA1 CFA0

000000

D7 D6 D5 D4 D3 D2 D1 D0

C1B23 C1B22 C1B21 C1B20 C1B19 C1B18 C1B17 C1B16

00000000

D7 D6 D5 D4 D3 D2 D1 D0

C1B15 C1B14 C1B13 C1B12 C1B11 C1B10 C1B9 C1B8

00000000

D7 D6 D5 D4 D3 D2 D1 D0

C1B7 C1B6 C1B5 C1B4 C1B3 C1B2 C1B1 C1B0

00000000

STA350BW Register description

Doc ID 018572 Rev 3 63/86

7.12.5 Coefficient b2 data register bits 23:16

7.12.6 Coefficient b2 data register bits 15:8

7.12.7 Coefficient b2 data register bits 7:0

7.12.8 Coefficient a1 data register bits 23:16

7.12.9 Coefficient a1 data register bits 15:8

7.12.10 Coefficient a1 data register bits 7:0

7.12.11 Coefficient a2 data register bits 23:16

D7 D6 D5 D4 D3 D2 D1 D0

C2B23 C2B22 C2B21 C2B20 C2B19 C2B18 C2B17 C2B16

00000000

D7 D6 D5 D4 D3 D2 D1 D0

C2B15 C2B14 C2B13 C2B12 C2B11 C2B10 C2B9 C2B8

00000000

D7 D6 D5 D4 D3 D2 D1 D0

C2B7 C2B6 C2B5 C2B4 C2B3 C2B2 C2B1 C2B0

00000000

D7 D6 D5 D4 D3 D2 D1 D0

C1B23 C1B22 C1B21 C1B20 C1B19 C1B18 C1B17 C1B16

00000000

D7 D6 D5 D4 D3 D2 D1 D0

C3B15 C3B14 C3B13 C3B12 C3B11 C3B10 C3B9 C3B8

00000000

D7 D6 D5 D4 D3 D2 D1 D0

C3B7 C3B6 C3B5 C3B4 C3B3 C3B2 C3B1 C3B0

00000000

D7 D6 D5 D4 D3 D2 D1 D0

C4B23 C4B22 C4B21 C4B20 C4B19 C4B18 C4B17 C4B16

00000000

64/86 Doc ID 018572 Rev 3

7.12.12 Coefficient a2 data register bits 15:8

7.12.13 Coefficient a2 data register bits 7:0

7.12.14 Coefficient b0 data register bits 23:16

7.12.15 Coefficient b0 data register bits 15:8

7.12.16 Coefficient b0 data register bits 7:0

7.12.17 Coefficient write/read control register

Coefficients for user-defined EQ, mixing, scaling, and bass management are handled

internally in the STA350BW via RAM. Access to this RAM is available to the user via an I2C

coefficient base address, five sets of three store the values of the 24-bit coefficients to be

written or that were read, and one contains bits used to control the write/read of the

coefficient(s) to/from RAM.

Three different RAM banks are embedded in the STA350BW. The three banks are managed

in paging mode using EQCFG register bits. They can be used to store different EQ settings.

For speaker frequency compensation, a sampling frequency independent EQ must be

implemented. Computing three different coefficients set for 32 kHz, 44.1kHz, 48 kHz and

downloading them into the three RAM banks, it is possible to select the suitable RAM block

depending on the incoming frequency with a simple I2C write operation in register 0x31.

D7 D6 D5 D4 D3 D2 D1 D0

C4B15 C4B14 C4B13 C4B12 C4B11 C4B10 C4B9 C4B8

00000000

D7 D6 D5 D4 D3 D2 D1 D0

C4B7 C4B6 C4B5 C4B4 C4B3 C4B2 C4B1 C4B0

00000000

D7 D6 D5 D4 D3 D2 D1 D0

C5B23 C5B22 C5B21 C5B20 C5B19 C5B18 C5B17 C5B16

00000000

D7 D6 D5 D4 D3 D2 D1 D0

C5B15 C5B14 C5B13 C5B12 C5B11 C5B10 C5B9 C5B8

00000000

D7 D6 D5 D4 D3 D2 D1 D0

C5B7 C5B6 C5B5 C5B4 C5B3 C5B2 C5B1 C5B0

00000000

D7 D6 D5 D4 D3 D2 D1 D0

Reserved RA R1 WA W1

0 0000

STA350BW Register description

Doc ID 018572 Rev 3 65/86

For example, in case of different input sources (different sampling rates), the three different

sets of coefficients can be downloaded once at startup, and during normal play it is possible

to switch among the three RAM blocks allowing faster operation, without any additional

download from the microcontroller.

To write the coefficients in a particular RAM bank, this bank must be selected first, writing

bit 0 and bit 1 in register 0x31. Then the write procedure below can be used.

Note that as soon as a RAM bank is selected, the EQ settings are automatically switched to

the coefficients stored in the active RAM block.

Note: The read and write operation on RAM coefficients works only if LRCKI (pin 29) is switching.

Reading a coefficient from RAM

1. Select the RAM block with register 0x31 bit 1, bit 0.

2. Write 6 bits of address to I2C register 0x16.

3. Write 1 to R1 bit in I2C address 0x26.

4. Read top 8 bits of coefficient in I2C address 0x17.

5. Read middle 8 bits of coefficient in I2C address 0x18.

6. Read bottom 8 bits of coefficient in I2C address 0x19.

Reading a set of coefficients from RAM

1. Select the RAM block with register 0x31 bit1, bit0.

2. Write 6 bits of address to I2C register 0x16.

3. Write 1 to RA bit in I2C address 0x26.

4. Read top 8 bits of coefficient in I2C address 0x17.

5. Read middle 8 bits of coefficient in I2C address 0x18.

6. Read bottom 8 bits of coefficient in I2C address 0x19.

7. Read top 8 bits of coefficient b2 in I2C address 0x1A.

8. Read middle 8 bits of coefficient b2 in I2C address 0x1B.

9. Read bottom 8 bits of coefficient b2 in I2C address 0x1C.

10. Read top 8 bits of coefficient a1 in I2C address 0x1D.

11. Read middle 8 bits of coefficient a1 in I2C address 0x1E.

12. Read bottom 8 bits of coefficient a1 in I2C address 0x1F.

13. Read top 8 bits of coefficient a2 in I2C address 0x20.

14. Read middle 8 bits of coefficient a2 in I2C address 0x21.

15. Read bottom 8 bits of coefficient a2 in I2C address 0x22.

16. Read top 8 bits of coefficient b0 in I2C address 0x23.

17. Read middle 8 bits of coefficient b0 in I2C address 0x24.

18. Read bottom 8 bits of coefficient b0 in I2C address 0x25.

66/86 Doc ID 018572 Rev 3

Writing a single coefficient to RAM

1. Select the RAM block with register 0x31 bit1, bit0.

2. Write 6 bits of address to I2C register 0x16.

3. Write top 8 bits of coefficient in I2C address 0x17.

4. Write middle 8 bits of coefficient in I2C address 0x18.

5. Write bottom 8 bits of coefficient in I2C address 0x19.

6. Write 1 to the W1 bit in I2C address 0x26.

Writing a set of coefficients to RAM

1. Select the RAM block with register 0x31 bit1, bit0.

2. Write 6 bits of starting address to I2C register 0x16.

3. Write top 8 bits of coefficient b1 in I2C address 0x17.

4. Write middle 8 bits of coefficient b1 in I2C address 0x18.

5. Write bottom 8 bits of coefficient b1 in I2C address 0x19.

6. Write top 8 bits of coefficient b2 in I2C address 0x1A.

7. Write middle 8 bits of coefficient b2 in I2C address 0x1B.

8. Write bottom 8 bits of coefficient b2 in I2C address 0x1C.

9. Write top 8 bits of coefficient a1 in I2C address 0x1D.

10. Write middle 8 bits of coefficient a1 in I2C address 0x1E.

11. Write bottom 8 bits of coefficient a1 in I2C address 0x1F.

12. Write top 8 bits of coefficient a2 in I2C address 0x20.

13. Write middle 8 bits of coefficient a2 in I2C address 0x21.

14. Write bottom 8 bits of coefficient a2 in I2C address 0x22.

15. Write top 8 bits of coefficient b0 in I2C address 0x23.

16. Write middle 8 bits of coefficient b0 in I2C address 0x24.

17. Write bottom 8 bits of coefficient b0 in I2C address 0x25.

18. Write 1 to the WA bit in I2C address 0x26.

The mechanism for writing a set of coefficients to RAM provides a method of updating the

five coefficients corresponding to a given biquad (filter) simultaneously to avoid possible

unpleasant acoustic side-effects. When using this technique, the 6-bit address specifies the

address of the biquad b1 coefficient (for example, 0, 5, 10, 20, 35 decimal), and the

STA350BW generates the RAM addresses as offsets from this base value to write the

complete set of coefficient data.

STA350BW Register description

Doc ID 018572 Rev 3 67/86

7.12.18 User-defined EQ

The STA350BW can be programmed for four EQ filters (biquads) per each of the two input

channels. The biquads use the following equation:

Y[n] = 2 * (b0 / 2) * X[n] + 2 * (b1 / 2) * X[n-1] + b2 * X[n-2] - 2 * (a1 / 2) * Y[n-1] - a2 * Y[n-2]

= b0 * X[n] + b1 * X[n-1] + b2 * X[n-2] - a1 * Y[n-1] - a2 * Y[n-2]

where Y[n] represents the output and X[n] represents the input. Multipliers are 24-bit signed

fractional multipliers, with coefficient values in the range of 0x800000 (-1) to 0x7FFFFF

(0.9999998808).

Coefficients stored in the user-defined coefficient RAM are referenced in the following

manner:

CxHy0 = b1 / 2

CxHy1 = b2

CxHy2 = -a1 / 2

CxHy3 = -a2

CxHy4 = b0 / 2

where x represents the channel and the y the biquad number. For example, C2H41 is the b2

coefficient in the fourth biquad for channel 2.

Additionally, the STA350BW can be programmed for a high-pass filter (processing

channels 1 and 2) and a low-pass filter (processing channel 3) to be used for bass-

management crossover when the XO setting is 000 (user-defined). Both of these filters

when defined by the user (rather than using the preset crossover filters) are second order

filters that use the biquad equation given above. They are loaded into the C12H0-4 and

C3Hy0-4 areas of RAM noted in Ta b l e 7 0 .

By default, all user-defined filters are pass-through where all coefficients are set to 0, except

the b0/2 coefficient which is set to 0x400000 (representing 0.5).

7.12.19 Pre-scale

The STA350BW provides a multiplication for each input channel for the purpose of scaling

the input prior to EQ. This pre-EQ scaling is accomplished by using a 24-bit signed

fractional multiplier, with 0x800000 = -1 and 0x7FFFFF = 0.9999998808. The scale factor

for this multiplication is loaded into RAM using the same I2C registers as the biquad

coefficients and the bass-management. All channels can use the channel-1 pre-scale factor

by setting the Biquad link bit. By default, all pre-scale factors are set to 0x7FFFFF.

7.12.20 Post-scale

The STA350BW provides one additional multiplication after the last interpolation stage and

the distortion compensation on each channel. This post-scaling is accomplished by using a

24-bit signed fractional multiplier, with 0x800000 = -1 and 0x7FFFFF = 0.9999998808. The

scale factor for this multiplication is loaded into RAM using the same I2C registers as the

biquad coefficients and the bass-management. This post-scale factor can be used in

conjunction with an ADC equipped microcontroller to perform power-supply error correction.

All channels can use the channel-1 post-scale factor by setting the post-scale link bit. By

default, all post-scale factors are set to 0x7FFFFF. When line output is being used,

channel-3 post-scale will affect both channels 3 and 4.

68/86 Doc ID 018572 Rev 3

7.12.21 Overcurrent post-scale

The STA350BW provides a simple mechanism for reacting to overcurrent detection in the

power block. When the ocwarn input is asserted, the overcurrent post-scale value is used in

place of the normal post-scale value to provide output attenuation on all channels. The

default setting provides 3 dB of output attenuation when ocwarn is asserted.

The amount of attenuation to be applied in this situation can be adjusted by modifying the

Overcurrent Post-scale value. As with the normal post-scale, this scaling value is a 24-bit

signed fractional multiplier, with 0x800000 = -1 and 0x7FFFFF = 0.9999998808. By default,

the overcurrent post-scale factor is set to 0x5A9DF7. Once the overcurrent attenuation is

applied, it remains until the device is reset.

Table 70. RAM block for biquads, mixing, scaling and bass management

Index (decimal) Index (hex) Coefficient Default

0 0x00

Channel 1 - Biquad 1

C1H10(b1/2) 0x000000

1 0x01 C1H11(b2) 0x000000

2 0x02 C1H12(a1/2) 0x000000

3 0x03 C1H13(a2) 0x000000

4 0x04 C1H14(b0/2) 0x400000

5 0x05 Channel 1 - Biquad 2 C1H20 0x000000

…… … … …

19 0x13 Channel 1 - Biquad 4 C1H44 0x400000

20 0x14 Channel 2 - Biquad 1 C2H10 0x000000

21 0x15 C2H11 0x000000

…… … … …

39 0x27 Channel 2 - Biquad 4 C2H44 0x400000

40 0x28

Channel 1/2 - Biquad 5

for XO = 000

Hi-pass 2nd Order filter

for XO≠000

C12H0(b1/2) 0x000000

41 0x29 C12H1(b2) 0x000000

42 0x2A C12H2(a1/2) 0x000000

43 0x2B C12H3(a2) 0x000000

44 0x2C C12H4(b0/2) 0x400000

45 0x2D

Channel 3 - Biquad

for XO = 000

Low-pass 2nd Order filter

for XO≠000

C3H0(b1/2) 0x000000

46 0x2E C3H1(b2) 0x000000

47 0x2F C3H2(a1/2) 0x000000

48 0x30 C3H3(a2) 0x000000

49 0x31 C3H4(b0/2) 0x400000

50 0x32 Channel 1 - Pre-Scale C1PreS 0x7FFFFF

51 0x33 Channel 2 - Pre-Scale C2PreS 0x7FFFFF

52 0x34 Channel 1 - Post-Scale C1PstS 0x7FFFFF

53 0x35 Channel 2 - Post-Scale C2PstS 0x7FFFFF

STA350BW Register description

Doc ID 018572 Rev 3 69/86

7.13 Variable max power correction registers (addr 0x27 - 0x28)

The MPCC bits determine the 16 MSBs of the MPC compensation coefficient. This

coefficient is used in place of the default coefficient when MPCV = 1.

7.14 Variable distortion compensation registers (addr 0x29 -

0x2A)

The DCC bits determine the 16 MSBs of the distortion compensation coefficient. This

coefficient is used in place of the default coefficient when DCCV = 1.

54 0x36 Channel 3 - Post-Scale C3PstS 0x7FFFFF

55 0x37 TWARN/OC - Limit TWOCL 0x5A9DF7

56 0x38 Channel 1 - Mix 1 C1MX1 0x7FFFFF

57 0x39 Channel 1 - Mix 2 C1MX2 0x000000

58 0x3A Channel 2 - Mix 1 C2MX1 0x000000

59 0x3B Channel 2 - Mix 2 C2MX2 0x7FFFFF

60 0x3C Channel 3 - Mix 1 C3MX1 0x400000

61 0x3D Channel 3 - Mix 2 C3MX2 0x400000

62 0x3E UNUSED

63 0x3F UNUSED

Table 70. RAM block for biquads, mixing, scaling and bass management (continued)

Index (decimal) Index (hex) Coefficient Default

D7 D6 D5 D4 D3 D2 D1 D0

MPCC15 MPCC14 MPCC13 MPCC12 MPCC11 MPCC10 MPCC9 MPCC8

00011010

D7 D6 D5 D4 D3 D2 D1 D0

MPCC7 MPCC6 MPCC5 MPCC4 MPCC3 MPCC2 MPCC1 MPCC0

11000000

D7 D6 D5 D4 D3 D2 D1 D0

DCC15 DCC14 DCC13 DCC12 DCC11 DCC10 DCC9 DCC8

1111001 1

D7 D6 D5 D4 D3 D2 D1 D0

DCC7 DCC6 DCC5 DCC4 DCC3 DCC2 DCC1 DCC0

00110011

70/86 Doc ID 018572 Rev 3

7.15 Fault detect recovery constant registers (addr 0x2B - 0x2C)

The FDRC bits specify the 16-bit fault detect recovery time delay. When FAULT is asserted,

the TRISTATE output is immediately asserted low and held low for the time period specified

by this constant. A constant value of 0x0001 in this register is approximately 0.083 ms. The

default value of 0x000C gives approximately 0.1 ms.

7.16 Device status register (addr 0x2D)

This read-only register provides fault and thermal-warning status information from the power

control block. Logic value 1 for faults or warning means normal state. Logic 0 means a fault

or warning detected on power bridge. The PLLUL = 1 means that the PLL is not locked.

D7 D6 D5 D4 D3 D2 D1 D0

FDRC15 FDRC14 FDRC13 FDRC12 FDRC11 FDRC10 FDRC9 FDRC8

00000000

D7 D6 D5 D4 D3 D2 D1 D0

FDRC7 FDRC6 FDRC5 FDRC4 FDRC3 FDRC2 FDRC1 FDRC0

00001100

D7 D6 D5 D4 D3 D2 D1 D0

PLLUL FAULT UVFAULT OVFAULT OCFAULT OCWARN TFAULT TWARN

Table 71. Status register bits

Bit R/W RST Name Description

7 R - PLLUL 0: PLL locked

1: PLL not locked

6R - FAULT 0: fault detected on power bridge

1: normal operation

5R - UVFAULT

0: VCCxX internally detected

< undervoltage threshold

4R - OVFAULT

0: VCCxX internally detected

> overvoltage threshold

3 R - OCFAULT 0: overcurrent fault detected

2 R - OCWARN 0: overcurrent warning

1R - TFAULT0: thermal fault, junction temperature over limit

detection

0R - TWARN0: thermal warning, junction temperature is close to

the fault condition

STA350BW Register description

Doc ID 018572 Rev 3 71/86

7.17 EQ coefficients and DRC configuration register (addr 0x31)

Bits AMGC[3:2] change the behavior of the bits AMGC[1:0] as given in Ta b l e 7 3 below.

When AMGC[3:2] = 01 then the bits 1:0 are defined as given here in Ta bl e 7 4 .

The AC0, AC1, AC2 settings are designed for the loudspeaker protection function, limiting at

the minimum any audio artifacts introduced by typical anti-clipping/DRC algorithms. More

detailed information is available in the applications notes “Configurable output power rate

using STA335BW” and “STA335BWS vs STA335BW”.

The XOB bit can be used to bypass the crossover filters. Logic 1 means that the function is

not active. In this case, the high-pass crossover filter works as a pass-through on the data

path (b0 = 1, all the other coefficients at logic 0) while the low-pass filter is configured to

have zero signal on channel-3 data processing (all the coefficients are at logic 0).

D7 D6 D5 D4 D3 D2 D1 D0

XOB Reserved Reserved AMGC[3] AMGC[2] Reserved SEL[1] SEL[0]

00000000

Table 72. EQ RAM select

SEL[1:0] EQ RAM bank selected

00/11 Bank 0 activated

01 Bank 1 activated

10 Bank 2 activated

Table 73. Anti-clipping and DRC preset

AMGC[3:2] Anti clipping and DRC preset selected

00 DRC/Anti-clipping behavior described in Ta b l e 5 3 on page 53 (default).

01 DRC/Anti-clipping behavior is described Table 74 on page 71

10/11 Reserved, do not use

Table 74. Anti-clipping selection for AMGC[3:2] = 01

AMGC[1:0] Mode

00 AC0, stereo anticlipping 0 dB limiter

01 AC1, stereo anticlipping +1.25 dB limiter

10 AC2, stereo anticlipping +2 dB limiter

11 Reserved do not use

72/86 Doc ID 018572 Rev 3

7.18 Extended configuration register (addr 0x36)

The extended configuration register provides access to B2DRC and biquad 5, 6 and 7.

7.18.1 Dual-band DRC

The STA350BW device provide a dual-band DRC (B2DRC) on the left and right channels

data path, as depicted in Figure 29. Dual-band DRC is activated by setting MDRC[1:0] = 1x.

Figure 29. B2DRC scheme

The low frequency information (LFE) is extracted from left and right channels, removing the

high frequencies using a programmable Biquad filter, and then computing the difference with

the original signal. Limiter 1 (DRC1) is then used to control Left/Right high-frequency

amplitude of the components, while limiter 2 (DRC2) is used to control the low-frequency

components (see Chapter 7.11).

The cutoff frequency of the high-pass filters can be user-defined, XO[3:0] = 0, or selected

from the pre-defined values.

DRC1 and DRC2 are then used to independently limit L/R high frequencies and LFE

channels amplitude (see Chapter 7.11) as well as their volume control. To be noted that, in

this configuration, the dedicated channel 3 volume control can actually act as a bass boost

enhancer as well (0.5 dB/step resolution).

The processed LFE channel is then recombined with the L and R channels in order to

reconstruct the 2.0 output signal.

Sub-band decomposition

The sub-band decomposition for B2DRC can be configured specifying the cutoff frequency.

The cutoff frequency can be programmed in two ways, using XO bits in register 0x0C, or

using the “user programmable” mode (coefficients stored in RAM addresses 0x28 to 0x31).

D7 D6 D5 D4 D3 D2 D1 D0

Mdrc[1] Mdrc[0] PS48DB XAR1 XAR2 BQ5 BQ6 BQ7

00000000

Pass XO

Filter

Pass XO

Filter

B2DRC

Hi-pass

filter

B2DRC

Hi-pass

filter -

CH1

Volume

VolAndLimiter

DRC1

CH2

Volume DRC1

CH3

Volume

VolAndLimiter

DRC2

CH3

Volume

VolAndLimiter

DRC2

Pass XO

Filter

Pass XO

Filter

B2DRC

Hi-pass

filter

B2DRC

Hi-pass

filter -

CH1

Volume

VolAndLimiter

DRC1

CH2

Volume DRC1

CH3

Volume

VolAndLimiter

DRC2

CH3

Volume

VolAndLimiter

DRC2

AM045194v1

STA350BW Register description

Doc ID 018572 Rev 3 73/86

For the user programmable mode, use the formulas below to compute the high-pass filters:

where alpha = (1-sin(ω0))/cos(ω0), and ω0 is the cutoff frequency.

A first-order filter is suggested to guarantee that for every ω0 the corresponding low-pass

filter obtained as the difference (as shown in Figure 29) will have a symmetric (relative to HP

filter) frequency response, and the corresponding recombination after the DRC has low

ripple. Second-order filters can be used as well, but in this case the filter shape must be

carefully chosen to provide good low-pass response and minimum ripple recombination. For

second-order filters it is not possible to give a closed formula to get the best coefficients, but

empirical adjustment should be done.

DRC settings

The DRC blocks used by B2DRC are the same as those described in Chapter 7.11. B2DRC

configure automatically the DRC blocks in anticlipping mode. Attack and release thresholds

can be selected using registers 0x32, 0x33, 0x34, 0x35, while attack and release rates are

configured by registers 0x12 and 0x14.

Band downmixing

The low-frequency band is down-mixed to the left and right channels at the B2DRC output.

Channel volume can be used to weight the bands recombination to fine-tune the overall

frequency response.

7.18.2 EQ DRC mode

Setting MDRC = 01, it is possible to add a programmable biquad (the XO biquad at RAM

addresses 0x28 to 0x2C is used for this purpose) to the Limiter/compressor measure path

(side chain). Using EQDRC the peak detector input can be shaped in frequency using the

programmable biquad. For example if a +2 dB bass boost is applied (using a low shelf filter

for example), the effect is that the EQDRC output will limit bass frequencies to -2 dB below

the selected attack threshold.

Generally speaking, if the biquad boosts frequency f with an amount of X dB, the level of a

compressed sine wave at the output will be TH - X, where TH is the selected attack

threshold.

Note: EQDRC works only if the biquad frequency response magnitude is ≥0dB for every

frequency.

b0 = (1 + alpha) / 2 a0 = 1

b1 = -(1 + alpha) / 2 a1 = -alpha

b2 = 0 a2 = 0

74/86 Doc ID 018572 Rev 3

Figure 30. EQDRC scheme

7.18.3 Extended post-scale range

Post-scale is an attenuation by default. When PS48DB is set to 1, a 48-dB offset is applied

to the coefficient RAM value, so post-scale can act as a gain too.

7.18.4 Extended attack rate

The attack rate shown in Ta b l e 6 4 can be extended to provide up to an 8 dB/ms attack rate

on both limiters.

Channel In

Channel In BIQUAD

EQDRC

Standard DRC

Channel In

Channel In BIQUADBIQUAD PEAK

DETECTOR

PEAK

DETECTOR

ATTENUATION

CLACULATOR

ATTENUATION

CLACULATOR

ATTENUATION

Channel In

Channel In BIQUAD

EQDRC

Standard DRC

Channel In

Channel In BIQUADBIQUAD PEAK

DETECTOR

PEAK

DETECTOR

ATTENUATION

CLACULATOR

ATTENUATION

CLACULATOR

ATTENUATION

AM045195v1

PS48DB Mode

0 Post-scale value is applied as defined in coefficient RAM

1Post-scale value is applied with +48 dB offset with respect to the

coefficient RAM value

XAR1 Mode

0 Limiter1 attack rate is configured using Ta bl e 6 4

1 Limiter1 attack rate is 8 dB/ms

XAR2 Mode

0 Limiter2 attack rate is configured using Ta bl e 6 4

1 Limiter2 attack rate is 8 dB/ms

STA350BW Register description

Doc ID 018572 Rev 3 75/86

7.18.5 Extended BIQUAD selector

De-emphasis filter as well as bass and treble controls can be configured as user-defined

filters when the equalization coefficients link is activated (BQL = 1) and the corresponding

BQx bit is set to 1.

When filters from 5th to 7th are configured as user-programmable, the corresponding

coefficients are stored respectively in addresses 0x20-0x24 (BQ5), 0x25-0x29 (BQ6), 0x2A-

0x2E (BQ7) as in Ta b le 7 0 .

Note: BQx bits are ignored if BQL = 0 or if DEMP = 1 (relevant for BQ5) or CxTCB = 1 (relevant for

BQ6 and BQ7).

7.19 EQ soft-volume configuration registers (addr 0x37 - 0x38)

The soft-volume update has a fixed rate by default. Using register 0x37 and 0x38 it is

possible to override the default behavior allowing different volume change rates.

It is also possible to independently define the fade-in (volume is increased) and fade-out

(volume is decreased) rates according to the desired behavior.

BQ5 Mode

0 Pre-set de-emphasis filter selected

1 User-defined biquad 5 coefficients are selected

BQ6 Mode

0 Pre-set bass filter selected as per Ta b le 6 3

1 User-defined biquad 6 coefficients are selected

BQ7 Mode

0 Pre-set treble filter selected as per Ta bl e 6 3

1 User-defined biquad 7 coefficients are selected

D7 D6 D5 D4 D3 D2 D1 D0

SVUPE SVUP[4] SVUP[3] SVUP[2] SVUP[1] SVUP[0]

00000000

D7 D6 D5 D4 D3 D2 D1 D0

SVDWE SVDW4] SVDW[3] SVDW[2] SVDW[1] SVDW[0]

00000000

SVUPE Mode

0 When volume is increased, use the default rate

1 When volume is increased, use the rates defined by SVUP[4:0]

76/86 Doc ID 018572 Rev 3

When SVUPE = 1 the fade-in rate is defined by the SVUP[4:0] bits according to the following

formula:

Fade-in rate = 48 / (N + 1) dB/ms

where N is the SVUP[4:0] value.

When SVDWE = 1 the fade-out rate is defined by the SVDW[4:0] bits according to the

following formula:

Fade-in rate = 48 / (N + 1) dB/ms

where N is the SVDW[4:0] value.

Note: For fade-out rates greater than 6 dB/msec it is suggested to disable the CPWMEN bit

(Section 7.24.4 ) and ZCE bit (Section 7.5.7) in order to avoid any audible pop noise.

7.20 DRC RMS filter coefficients (addr 0x39-0x3E)

Signal level detection in DRC algorithm is computed using the following formula:

y(t) = c0 * abs(x(t)) + c1 * y(t-1)

where x(t) represents the audio signal applied to the limiter, and y(t) the measured level.

SVDWE Mode

0 When volume is decreased, use the default rate

1 When volume is decreased, use the rates defined by SVDW[4:0]

D7 D6 D5 D4 D3 D2 D1 D0

R_C0[23] R_C0[22] R_C0[21] R_C0[20] R_C0[19] R_C0[18] R_C0[17] R_C0[16]

00000001

D7 D6 D5 D4 D3 D2 D1 D0

R_C0[15] R_C0[14] R_C0[13] R_C0[12] R_C0[11] R_C0[10] R_C0[9] R_C0[8]

11101110

D7 D6 D5 D4 D3 D2 D1 D0

R_C0[7] R_C0[6] R_C0[5] R_C0[4] R_C0[3] R_C0[2] R_C0[1] R_C0[0]

11111111

D7 D6 D5 D4 D3 D2 D1 D0

R_C1[23] R_C1[22] R_C1[21] R_C1[20] R_C1[19] R_C1[18] R_C1[17] R_C1[16]

01111110

D7 D6 D5 D4 D3 D2 D1 D0

R_C1[15] R_C1[14] R_C1[13] R_C1[12] R_C1[11] R_C1[10] R_C1[9] R_C1[8]

11000000

D7 D6 D5 D4 D3 D2 D1 D0

R_C1[7] R_C1[6] R_C1[5] R_C1[4] R_C1[3] R_C1[2] R_C1[1] R_C1[0]

00100110

STA350BW Register description

Doc ID 018572 Rev 3 77/86

7.21 Extra volume resolution configuration registers (address

0x3F)

The extra volume resolution allows fine volume tuning by steps of 0.125dB.

The feature is enabled when VRESEN=1 , as depicted in Figure 31. The overall channel

volume in this case will be CxVol+CxVR (in dB). On top of the total volume range from

-80 dB to +48 dB, this extra volume resolution works in a volume range from -80 dB to +42

dB. For volumes greater than +42 dB, this function must not be selected.

Figure 31. Extra resolution volume scheme

If VRESEN = 0 the channel volume will be defined only by the CxVol registers.

Fine-tuning steps can be set according to the following table for channels 1, 2, 3:

D7 D6 D5 D4 D3 D2 D1 D0

VRESEN VRESTG C3VR[1] C3VR[0] C2VR[1] C2VR[0] C1VR[1] C1VR[0]

00000000

CxVR Mode

00 0 dB

01 -0.125dB

10 -0.25dB

11 -0.375dB

Audio Data Out

CxVOL Soft

Volume

Audio Data In

VRESEN

VRESTG

CxVR

MVOL or CxVOL’event

Audio Data Out

CxVOL Soft

Volume

Audio Data In

VRESEN

VRESTG

CxVR

MVOL or CxVOL’event

AM045196v1

78/86 Doc ID 018572 Rev 3

Two different behaviors can be configured by the VRESTG bit:

●If VRESTG=’0’ the CxVR contribution will be applied immediately after the

corresponding I2C bits are written.

●If VRESTG=’1’ the CxVR bits will be effective on channel volume only after the

corresponding CxVol register or master volume register is written (even to the previous

values).

7.22 Quantization error noise correction (address 0x48)

A special feature inside the digital processing block is available. In case of poles positioned

at very low frequencies, biquad filters can generate some audible quantization noise or

unwanted DC level. In order to avoid this kind of effect, a quantization noise-shaping

capability can be used. The filter structure including this special feature, relative to each

biquad, is shown in Figure 32.

By default, this capability is not activated to maintain backward compatibility with all the

previous Sound Terminal products. The new feature can be enabled independently for each

biquad using the I2C registers. The D7 bit, when set, is responsible for activating this

function on the crossover filter while the other bits address any specific biquads according to

the previous table. Channels 1 and 2 share the same settings. Bit D7 is effective also for

channel 3 if the relative OCFG is used.

VRESEN VRESTG Mode

0 0 Extra Volume Resolution disabled

0 1 Extra Volume Resolution disabled

1 0 Volume fine-tuning enabled and applied immediately.

Volume fine-tuning enabled and applied when master or

channel volume is updated

D7 D6 D5 D4 D3 D2 D1 D0

NSHXEN NSHB7EN NSHB6EN NSHB5EN NSHB4EN NSHB3EN NSHB2EN NSHB1EN

00000000

STA350BW Register description

Doc ID 018572 Rev 3 79/86

Figure 32. Biquad filter structure with quantization error noise-shaping

7.23 Extended coefficient range up to -4...4 (address 0x49, 0x4A)

Biquads from 1 to 7 have in the STA350BW the possibility to extend the coefficient range

from [-1,1) to [-4..4). This allows the realization of high shelf filters that may require a

coefficients dynamic greater in absolute value than 1.

Three ranges are available, [-1;1) [-2;2) [-4;4). By default the extended range is not activated

to maintain backward compatibility with all the previous Sound Terminal products.

Each biquad has its independent setting according to the following table:

Table 75. Biquad filter settings

z-1

In(t) b0

z-1

Out(t)

z-1

In(t) b0

z-1

Out(t)

AM045197v1

D7 D6 D5 D4 D3 D2 D1 D0

CXTB4[1] CXTB4[0] CXTB3[1] CXTB3[0] CX_B2[1] CXTB2[0] CXTB1[1] CXTB1[0]

00000000

D7 D6 D5 D4 D3 D2 D1 D0

Reserved Reserved CXTB7[1] CXTB7[0] CXTB6[1] CXTB6[0] CXTB5[1] CXTB5[0]

0 0 00000 0

CEXT_Bx[1] CEXT_Bx[0]

[-1;1)

[-2;2)

[-4;4)

1 1 Reserved

80/86 Doc ID 018572 Rev 3

In this case the user can decide, for each filter stage, the right coefficients range. Note that

for a given biquad the same range will be applied to Left and Right (Channel 1 and Channel

2).

The crossover biquad does not have the availability of this feature, maintaining the [-1;1)

range unchanged.

7.24 Miscellaneous registers (address 0x4B, 0x4C)

7.24.1 Rate powerdown enable (RPDNEN) bit (address 0x4B, bit D7)

In the STA350BW, by default, the power-down pin and I2C power-down act on mute

commands to perform the fadeout. This default can be changed so that the fadeout can be

started using the master volume. The RPDNEN bit, when set, activates this feature.

7.24.2 Noise-shaping on DC cut filter enable (NSHHPEN) bit (address 0x4B,

bit D6)

Following the description in Section 7.22, this bit, when set, enables the noise-shaping

technique on the DC cutoff filter. Channels 1 and 2 share the same settings.

7.24.3 Bridge immediate off (BRIDGOFF) bit (address 0x4B, bit D5)

A fadeout procedure is started in the STA350BW once the PWDN function is enabled.

Independently from the fadeout time, after 13 million clock cycles (PLL internal frequency)

the bridge is put in powerdown (tristate mode). There is also the possibility to change this

behavior so that the power bridge will be switched off immediately after the PWDN pin is tied

to ground, without therefore waiting for the 13 million clock cycles. The BRIDGOFF bit, when

set, activates this function. Obviously the immediate power-down will generate a pop noise

at the output. therefore this procedure must be used only in case pop noise is not relevant in

the application. Note that this feature works only for hardware PWDN assertion and not for a

powerdown applied through the I2C interface. Refer to Section 7.24.5 in order to program a

different number of clock cycles.

D7 D6 D5 D4 D3 D2 D1 D0

RPDNEN NSHHPEN BRIDGOFF Reserved Reserved CPWMEN Reserved Reserved

0 0 0001 0 0

D7 D6 D5 D4 D3 D2 D1 D0

Reserved Reserved Reserved PNDLSL[2] PNDLSL[1] PNDLSL[0] Reserved Reserved

00000000

STA350BW Register description

Doc ID 018572 Rev 3 81/86

7.24.4 Channel PWM enable (CPWMEN) bit (address 0x4B, bit D2)

This bit, when set, activates a mute output in case the volume will reach a value lower than

-76 dBFS.

7.24.5 Power-down delay selector (PNDLSL[2:0]) bits (address 0x4C, bit D4,

D3, D2)

As per Section 7.24.3, the assertion of PWDN activates a counter that, by default, after 13

million clock cycles puts the power bridge in tristate mode, independently from the fadeout

time. Using these registers it is possible to program this counter according to the following

table:

PNDLSL[2] PNDLSL[1] PNDLSL[2] Fade out time

00 0 Default time (13M clock cycles)

00 1 Default time divided by 2

01 0 Default time divided by 4

01 1 Default time divided by 8

10 0 Default time divided by 16

10 1 Default time divided by 32

11 0 Default time divided by 64

11 1

Default time divided by 128

Package thermal characteristics STA350BW

82/86 Doc ID 018572 Rev 3

8 Package thermal characteristics

Using a four-layer PCB the thermal resistance junction-to-ambient with 2 copper ground

areas of 6 x 4 cm2 and with 24 via holes (see Figure 33) is 17 °C/W in natural air convection.

The dissipated power within the device depends primarily on the supply voltage, load

impedance and output modulation level.

Thus, the maximum estimated dissipated power for the STA350BW is:

Figure 33. Double-layer PCB with 2 copper ground areas and 24 via holes

Figure 34 shows the power derating curve for the PowerSSO-36 slug-down package on

PCBs with copper areas of 5 x 4 cm2 and 6 x 4cm2.

Figure 34. PowerSSO-36 power derating curve

2 x 40 W @ 8 Ω, 25.5 V Pd max ~ 8 W

2 x 17 W + 1 x 35 W @ 4 Ω, 8 Ω, 25 V Pd max < 7 W

AM045200v1

020406080 100 120 140 160

Pd (W)

Tamb( °C)

Copper Area 5x4 cm

and 20 via holes

STA350BW

Power-SSO36

Copper Area 6x4 cm

and 24 via holes

Copper Area 5x4 cm

and 20 via holes

STA350BW

Power-SSO36

Copper Area 6x4 cm

and 24 via holes

AM045201v1

STA350BW Package mechanical data

Doc ID 018572 Rev 3 83/86

9 Package mechanical data

In order to meet environmental requirements, ST offers these devices in different grades of

ECOPACK® packages, depending on their level of environmental compliance. ECOPACK®

specifications, grade definitions and product status are available at: www.st.com.

ECOPACK® is an ST trademark.

Table 76. PowerSSO-36 EPD dimensions

Symbol

Dimensions in mm Dimensions in inches

Min Typ Max Min Typ Max

A 2.15 - 2.47 0.085 - 0.097

A2 2.15 - 2.40 0.085 - 0.094

a1 0.00 - 0.10 0.00 - 0.004

b 0.18 - 0.36 0.007 - 0.014

c 0.23 - 0.32 0.009 - 0.013

D 10.10 - 10.50 0.398 - 0.413

E 7.40 - 7.60 0.291 - 0.299

e- 0.5 - - 0.020 -

e3 - 8.5 - - 0.335 -

F- 2.3 - - 0.091 -

G - - 0.10 - - 0.004

H 10.10 - 10.50 0.398 - 0.413

h - - 0.40 - - 0.016

k 0 - 8 degrees 0 - 8 degrees

L 0.60 - 1.00 0.024 - 0.039

M - 4.30 - - 0.169 -

N - - 10 degrees - - 10 degrees

O - 1.20 - - 0.047 -

Q - 0.80 - - 0.031 -

S - 2.90 - - 0.114 -

T - 3.65 - - 0.144 -

U - 1.00 - - 0.039 -

X 4.10 - 4.70 0.161 - 0.185

Y 6.50 - 7.10 0.256 - 0.280

STA350BW Package mechanical data

Doc ID 018572 Rev 3 84/86

Figure 35. PowerSSO-36 EPD outline drawing

h x 45°

STA350BW Revision history

Doc ID 018572 Rev 3 85/86

10 Revision history

Table 77. Document revision history

Date Revision Changes

11-Mar-2011 1Initial release.

20-Apr-2011 2 Updated Figure 4: Demonstration board, 2.0 channels

Added Figure 5: Mono parallel BTL schematic

13-Apr-2012 3 Updated min. and typ. values for Isc in Table 6: Electrical

specifications - power section

STA350BW

86/86 Doc ID 018572 Rev 3

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