Microsemi
Linfinity Microelectronics Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 1
Copyright © 2001
Rev. 1.2a,2004-06-10
WWW.Microsemi .COM
AudioMAX™ LX1721 / 1722
Class-D Stereo Power Amplifier Controller
P
RODUCTION
INTEGRATED PRODUCTS
DESCRIPTION
The LX1721/1722 is a monolithic high
performance Class-D stereo controller IC
designed for high efficiency or space
constrained audio requirements such as
portable or battery operated products,
automotive amplifiers, and multi-channel
multimedia computer and video game
applications. This high frequency, full
audio bandwidth switching power
amplifier controller offers dramatically
improved performance over Linfinity’s
p
revious generation amplifier products.
Enhancements include higher output
power, better SNR, lower noise floor, and
reduced THD. Combined with output
power MOSFET’s and an output filter, the
LX1721/1722 is a complete Class-D audio
solution.
A complete audio amplifier module is
available to quickly evaluate the LX1721
or LX1722 stereo controller. Simply
connect the amplifier to the power source,
audio signal, and speakers. Reference
designs support a variety of requirements
including multi channel systems,
subwoofers, satellite / subwoofer com-
binations and various speaker loads (2Ω,
4Ω, 8Ω). The versatile amplifier solution
can easily be adjusted for frequency
response, optimized for efficiency and
performance, or designed to minimize
PCB area and component count. The
LX1721/1722 is available in a space
saving 44-pin QSOP package.
(Continued Next Page)
IMPORTANT: For the most current data, consult MICROSEMI’s website: http://www.microsemi.com
PRODUCT HIGHLIGHT
LX1722
Stereo
FETs
FETs
LX1711
Mono FETs
IN +
IN -
IN +
IN -
IN +
IN -
CLOCK
Left
Right
Subwoofer
2Ω, 4Ω, 8Ω
Channel
1
Channel 2
Channel 3
7V - 25V
2.1 Audio Amplifier
Configuration
Output Power vs. Supply Voltage
1kHz, 4Ω, THD+N=1%
KEY FEATURES
Integrated Switching Class-D
Stereo Controller IC
Full 20Hz-20kHz Audio
Bandwidth
High Fidelity (LX1721) Or
High Power (LX1722)
Versions Available
Single Supply Operation
THD+N <0.06% Typical
(1Wrms, 1kHz, 4)
Maximum Efficiency 80%-
85%
Output Power >60Wrms per
Channel (LX1722, 4, 1%
THD+N)
PSRR –70dB Typical
Differential Input To Minimize
Noise Effects
Supports Multi-Channel
Systems
Complete LXE1721or
LXE1722 Amplifier Evaluation
Module Available
44-Pin QSOP Package
APPLICATIONS
Multimedia Speakers
Surround Sound Game
Systems
Notebook Computers
Desktop Computers
Automotive Amplifiers And
Head units
Battery Operated Equipment
(Megaphone, Public Address
System)
Portable Audio (Boom Box)
Wireless Speakers
High Power Subwoofer
Automotive Audio Systems
Home Theatre
PACKAGE ORDER INFO
TJ (°C) VDD DB Plastic QSOP
44-Pin
-20 to 70 7V – 15V LX1721CDB
-20 to 70 7V – 25V LX1722CDB
Note: Available in Tape & Reel.
Append the letters “TR” to the part number. (i.e. LX1722CDBTR)
L
LX
X1
17
72
21
1/
/2
22
2
Microsemi
Linfinity Microelectronics Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 2
Copyright © 2001
Rev. 1.2a,2004-06-10
WWW.Microsemi .COM
AudioMAX™ LX1721 / 1722
Class-D Stereo Power Amplifier Controller
P
RODUCTION
INTEGRATED PRODUCTS
THERMAL DATA
DB 44-PIN QSSOP PACKAGE
THERMAL RESISTANCE-JUNCTION TO AMBIENT, θJA 50°C/W
Junction Temperature Calculation: TJ = TA + (PD x θJA).
The θJA numbers are guidelines for the thermal performance of the device/pc-board
system. All of the above assume no ambient airflow.
PACKAGE PIN OUT
1
22 23
44
LFAOUT
CPWM
RPWM
LMUTE
LEAOUT
LEAIN
VREF
CLOCK
GND
V25
LIN+
LIN-
LAMPOUT
RIN+
RIN-
RAMPOUT
SLEEP
STATUS
RMUTE
REAIN
REAOUT
RFAOUT
LFBK-
LFBK+
LISN
VDD
CN
PVDD
PGND
LN+
LP+
LP-
LN-
RN-
RP-
RP+
RN+
PGND
CP
PVDD
NC
RISN
RFBK+
RFBK-
DB PACKAGE
(Top View)
DESCRIPTION (CONTINUTED)
The stereo output controller is available in either an
LX1722 high power version (>65Wrms, 4Ω) with a supply
voltage range of 7V-25V or an LX1721 high fidelity
version (better SNR performance) with a supply voltage
range of 7V-15V. The current rating of the external
MOSFET’s, the available supply voltage, and speaker load
primarily limits the maximum output power. The amplifier
provides high fidelity performance and is designed to
operate over the full 20Hz to 20kHz audio band. Signal
distortion measurements yield.
THD+N levels of 0.06%(1kHz, 1Wrms). Efficiency is
greater than 80% typical, which eliminates the need for
heatsinks in most applications. The AudioMAX™ solution
requires a single supply voltage, simplifying input power
requirements where a dual supply may not be available. To
minimize potential environmental noise issues and ease the
integration of the amplifier into a variety of applications,
features such as a balanced/differential audio input and a high
power supply rejection ratio help reduce the effects of noise
from the audio signal or power supply.
P
PA
AC
CK
KA
AG
GE
E
D
DA
AT
TA
A
Microsemi
Linfinity Microelectronics Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 3
Copyright © 2001
Rev. 1.2a,2004-06-10
WWW.Microsemi .COM
AudioMAX™ LX1721 / 1722
Class-D Stereo Power Amplifier Controller
P
RODUCTION
INTEGRATED PRODUCTS
FUNCTIONAL PIN DESCRIPTION
PIN NAME DESCRIPTION PIN NAME DESCRIPTION
LFAOUT Left Feedback Amplifier Output LFBK- Left Feedback Amplifier Inverting Input
CPWM PWM Capacitor Connection LFBK+ Left Feedback Amplifier Non-Inverting
Input
RPWM PWM Resistor Connection LISN Left Current Limit Sense Input
LMUTE Left Mute Input (Active High) VDD Analog Supply Voltage
LEAOUT Left Error Amplifier Output CN Supply Decoupling for NFET Drivers
LEAIN Left Inverting Input of Error Amplifier PVDD Output Driver Supply Voltage
VREF 5V Reference PGND Output Driver High Current Ground
CLOCK Input / Output Clock for Synch Operation LN+ Left Drive for NFET on Positive Half of
Bridge
GND Low Current Ground LP+ Left Drive for PFET on Positive Half of
Bridge
V25 2.5V Reference LP- Left Drive for PFET on Negative Half of
Bridge
LIN+ Left Positive Audio Input LN- Left Drive for NFET on Negative Half of
Bridge
LIN- Left Negative Audio Input RN- Right Drive for NFET on Negative Half of
Bridge
LAMPOUT Left Input Amplifier Output RP- Right Drive for PFET on Negative Half of
Bridge
RIN+ Right Positive Audio Input RP+ Right Drive for PFET on Positive Half of
Bridge
RIN- Right Negative Audio Input RN+ Right Drive for NFET on Positive Half of
Bridge
RAMPOUT Right Input Amplifier Output PGND Output Driver High Current Ground
SLEEP Sleep Input (active low) CP Supply Decoupling for PFET Drivers
STATUS UVLO Indicator (Open Collector Output) PVDD Output Driver Supply Voltage
RMUTE Right Mute Input (Active High) NC No Connect
REAIN Right Inverting Input of Error Amplifier RISN Right Current Limit Sense Input
REAOUT Right Error Amplifier Output RFBK+ Left Feedback Amplifier Non-Inverting
Input
RFAOUT Right Feedback Amplifier Output RFBK- Right Feedback Amplifier Inverting Input
ABSOLUTE MAXIMUM RATINGS
Supply Voltage (PVDD, VDD)............................................................................................................................. -0.3V to 30V
SLEEP , STATUS, R/LFBK+, R/LFBK- .................................................................................................-0.3V to VDD +0.3V
R/LISN .........................................................................................................................................PVDD –2 to PVDD to +0.3V
RPWM, CPWM, R/LMUTE ................................................................................................................... -0.3V to VREF +0.3V
R/LIN+, R/LIN-, R/LAMPOUT.............................................................................................................. -0.3V to VREF +0.3V
R/LEAIN, R/LEAOUT, R/LFAOUT ..................................................................................................... -0.3V to VREF + 0.3V
CLOCK ........................................................................................................................................................-0.3V to CN +0.3V
Operating Junction Temperature Plastic........................................................................................................................... 125°C
Storage Temperature Range ...............................................................................................................................-65°C to 150°C
Lead Temperature (Soldering, 10 seconds)...................................................................................................................... 300°C
Note: Exceeding these ratings could cause damage to the device. All voltages are with respect to Ground. Currents are positive into negative out of the
specified terminal.
P
PA
AC
CK
KA
AG
GE
E
D
DA
AT
TA
A
Microsemi
Linfinity Microelectronics Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 4
Copyright © 2001
Rev. 1.2a,2004-06-10
WWW.Microsemi .COM
AudioMAX™ LX1721 / 1722
Class-D Stereo Power Amplifier Controller
P
RODUCTION
INTEGRATED PRODUCTS
ELECTRICAL CHARACTERISTICS
Unless otherwise specified, the following specifications apply over the operating ambient temperature -20°C < TA < 70°C (NOTE 2).
Test conditions: RPWM = 34.8k, CPWM = 100pF, VDD = PVDD = 15V
LX1721 / 1722
Parameter Symbol Test Conditions Min Typ Max Units
Evaluation Module (See LXE1721)
Supply Voltage LX1721 7 15
LX1722
VDD 7 25
V
Power Supply Rejection Ratio PSRR VIN = 15V, VRIPPLE = 1VRMS, 20Hz
to 20kHz -70 dB
VIN = 15V, RL=4, THD+N=1%,
10Hz to 22kHz 25
Output Power (Per Channel) PO VIN = 25V, RL=4, THD+N=1%,
10Hz to 22kHz 60
W
VIN = 15V, fIN = 1kHz, PO = 10W 82
Efficiency
VIN = 15V, fIN = 1kHz, PO = 20W 85 %
fIN = 1kHz, PO = 1W .06
Total Harmonic Distortion Plus Noise THD+N fIN = 20Hz to 20kHz, PO = 1W .2 %
Signal-To-Noise Ratio SNR RL = 4Ω, PO = 1W 81 dBr
Oscillator Section
Oscillator Frequency FOSC 450 kHz
Charge Current ICHG (varies with VDD pin voltage) -225 µA
Discharge Current IDIS (varies with VDD pin voltage) 225 µA
Oscillator Peak Voltage VPK (varies with VDD pin voltage) 3.6 V
Oscillator Valley Voltage VVAL (varies with VDD pin voltage) 1.4 V
Voltage Stability VDD = 8V to 25V 0.6 2 %
Temperature Stability TA = 0OC to 70OC 1.0 2 %
Error Amplifier
Input Offset Voltage VIO 5 ‘mV
DC Open Loop Gain AOL 60 dB
Unity Gain Bandwidth UGBW 7 ‘MHz
High Output Voltage VOH IOUT = -100µA 3.5 V
Low Output Voltage VOL IOUT = +100µA 100 ‘mV
Input Bias Current IIN V
IN = 1V to 4V 1 µA
Input Amplifier
Stage Gain Set by Internal Resistors 3.465 3.5 3.535 V/V
Output Voltage, High VOH IOUT = -100µA 3.85 V
Output Voltage, Low VOL IOUT = +100µA 1.3 V
Input Impedance 180 ‘kΩ
Feedback Amplifier
Stage Gain LX1721 Set by Internal Resistors 89 91 93 ‘mV/V
LX1722 Set by Internal Resistors 56 57 58 ‘mV/V
Input Impedance LX1721 250 kΩ
LX1722 400
kΩ
E
EL
LE
EC
CT
TR
RI
IC
CA
AL
LS
S
Microsemi
Linfinity Microelectronics Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 5
Copyright © 2001
Rev. 1.2a,2004-06-10
WWW.Microsemi .COM
AudioMAX™ LX1721 / 1722
Class-D Stereo Power Amplifier Controller
P
RODUCTION
INTEGRATED PRODUCTS
ELECTRICAL CHARACTERISTICS (CONTINUED)
LX1721 / 1722
Parameter Symbol Test Conditions Min Typ Max Units
Current Limit Comparator
Voltage Sense Threshold 190 210 230 mV
Blanking Pulse Delay 500 ‘ns
Response Time Excluding blanking pulse 250 ‘ns
IUM Pulses required to Current Limit
Latch 4 4 4 ‘cycles
Consecutive Clear Pulses required to
reset IUM counter 2 2 2 ‘cycles
Reference Voltage Section
Initial Accuracy (VREF) 5.0
Voltage Stability (VREF) ± 50 ± 100 ‘mV
Initial Accuracy (V25) 2.5
Voltage Stability (V25) ± 25 ± 50 mV
Temperature Stability TA = 0OC to 70OC 2 5 ‘mV
Line Regulation VDD = 9V to 15V 0.5 ‘mV
Load Regulation IOUT = 0 to 10mA 5 ‘mV
Under Voltage Lockout Section
Start Threshold Voltage 6 V
UV Lockout Hysteresis 250 mV
UVLO Delay To Output Enable 62,500 clkcyc
Supply Current
Sleep Current SLEEP Input = 0V, TA = 25OC 30
µA
Operating Current SLEEP Input = 2V, VIN = 15V,
No MOSFETs connected 8 11 ‘mA
Sleep to Output Enable 62,500 clkcyc
Sleep Threshold 1.45 1.6 1.75 V
Mute Section
Mute Threshold 1.2 1.35 1.5 V
Output Drivers For N-Channel MOSFETs
ISINK = 3mA 30 100 ‘mV
NFET Drivers, Low Level Voltage VOL ISINK = 100mA 0.3 1.0 V
I
SOURCE = 3mA, CN = 5.2V
applied externally 30 100 ‘mV
NFET Drivers, High Level Voltage VOH ISOURCE = 100mA, CN = 5.2V
applied externally 0.3 1.0 V
Output Drives For P-Channel MOSFETs
ISINK = 3mA 30 100 ‘mV
PFET Drivers, Low Level Voltage VOL ISINK = 100mA 0.5 1.0 V
I
SOURCE = 3mA, CP = 5.2V
(applied externally) 30 100 ‘mV
PFET Drivers, High Level Voltage VOH ISOURCE = 100mA, CP = 5.2V
(applied externally) 0.5 1.0 V
Note 2: The LX1721 / 22CDB is guaranteed to meet performance specifications from 0° to 70°C. Specifications over the -20° to 0°C operation temperature
range are assured by design, characterization, and statistical process control.
E
EL
LE
EC
CT
TR
RI
IC
CA
AL
LS
S
Microsemi
Linfinity Microelectronics Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 6
Copyright © 2001
Rev. 1.2a,2004-06-10
WWW.Microsemi .COM
AudioMAX™ LX1721 / 1722
Class-D Stereo Power Amplifier Controller
P
RODUCTION
INTEGRATED PRODUCTS
BLOCK DIAGRAM
SLEEP
VREF
V25
CN
PVDD
CP
LP+
LN+
LP-
LN-
LFAOUT
LFBK-
LFBK+
VDD
LISN
CLOCK
RPWM
CPWM
LEAOUT
LEAIN
LAMPOUT
LIN-
LIN+
LMUTE
UVLO
&
REFERENCE
OUTPUT
DRIVERS
&
LOGIC
FAULT
TIMER
5V
Reference 28
10
7
17
CLK
OSC
SYNC
+
-220mV
PVDD
MUX
MUTE
MUTE
11
5
6
13
4
12
2
3
8
42
41
1
44
FEEDBACK AMP
ERROR AMP
CURRENT SENSE
INPUT AMP
43
27,39
36
37
34
35
S
R
Q
Q
CLK
5V
Reference 40
2.5V
2.5V
FIGURE 1 – LX1721 / 22 SIMPLIFIED BLOCK DIAGRAM (LEFT CHANNEL CIRCUIT SHOWN)
B
BL
LO
OC
CK
KD
DI
IA
AG
GR
RA
AM
M
Microsemi
Linfinity Microelectronics Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 7
Copyright © 2001
Rev. 1.2a,2004-06-10
WWW.Microsemi .COM
AudioMAX™ LX1721 / 1722
Class-D Stereo Power Amplifier Controller
P
RODUCTION
INTEGRATED PRODUCTS
APPLICATION INFORMATION
Frequency Synchronization
Two or more LX1721 / LX1722 oscillators can be configured for
synchronous operation. One unit, the master, is programmed for
the desired frequency with the RPWM and CPWM as usual.
Additional units will be slave units, and their oscillators will be
disabled by leaving the RPWM pin disconnected. The CLOCK pin
and the CPWM pin of the slave units should be tied to the CLOCK
pin and the CPWM pin of the master unit respectively. In this
configuration, the CLOCK pins of the slave units begin receiving
instead of transmitting clock pulses. Also, the CPWM pins quit
driving the PWM capacitor in the slave units. Note that for
optimum performance, all slave units should be located within a
few inches of the master unit.
Oscillator Configuration (RPWM and CPWM selection)
The oscillator is programmed by the external timing components
RPWM and CPWM. For a nominal frequency of 333kHz, RPWM and
CPWM should be set to 49.9kOhms and 100pF respectively. Note that
in order to keep the slope of the PWM ramp voltage proportional to
the supply voltage, both the ramp peak and valley voltages, and the
charge and discharge currents are proportional to the supply voltage.
This keeps the frequency relatively constant while keeping the slope
of the PWM ramp proportional to the voltage on the VDD pin. For
operating frequencies other than 333kHz, the frequency can be
approximated by the following equation:
nsCR PWMPWM 320))()(577.0(
1
Frequency +
=
A
AP
PP
PL
LI
IC
CA
AT
TI
IO
ON
N
Microsemi
Linfinity Microelectronics Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 8
Copyright © 2001
Rev. 1.2a,2004-06-10
WWW.Microsemi .COM
AudioMAX™ LX1721 / 1722
Class-D Stereo Power Amplifier Controller
P
RODUCTION
INTEGRATED PRODUCTS
CHARACTERISTIC CURVES
THD+N (%)
0.001
100
0.002
0.005
0.01
0.02
0.05
0.1
0.2
0.5
1
2
5
10
20
50
0.24563
0.06751
100m 100200m 500m 1 2 510 20 50
19.12.9161
Output Power (W)
dx=-18.20 W dy=-0.17812 %
FIGURE 2 – THD+N VS. OUTPUT POWER
VIN = 15V
fIN = 1kHz
RL = 4Ω
THD+N (%)
0.001
100
0.002
0.005
0.01
0.02
0.05
0.1
0.2
0.5
1
2
5
10
20
50
0.0629
0.53924
100m 100200m 500m 1 2 510 20 50
1.225 59.95
Output Power (W)
dx=58.73 W dy=0.47633 %
FIGURE 3 – THD+N VS. OUTPUT POWER
VIN = 25V
fIN = 1kHz
RL = 4Ω
THD+N (%)
0.001
100
0.002
0.005
0.01
0.02
0.05
0.1
0.2
0.5
1
2
5
10
20
50
0.26783
0.04397
100m 100200m 500m 1 2 510 20 50
38.241.252
Output Power (W)
dx=-36.99 W dy=-0.22386 %
FIGURE 4 – THD+N VS. OUTPUT POWER
VIN = 15V
fIN = 1kHz
RL = 2Ω
G
GR
RA
AP
PH
HS
S
Microsemi
Linfinity Microelectronics Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 9
Copyright © 2001
Rev. 1.2a,2004-06-10
WWW.Microsemi .COM
AudioMAX™ LX1721 / 1722
Class-D Stereo Power Amplifier Controller
P
RODUCTION
INTEGRATED PRODUCTS
CHARACTERISTIC CURVES (CONTINUED)
0.001
100
0.002
0.005
0.01
0.02
0.05
0.1
0.2
0.5
1
2
5
10
20
50
0.05123
0.53924
THD+N(%)
100m 300200m 500m 1 2 5 10 20 50 100 200
1.136 109.9
Output Power (W)
dx=108.8 W dy=0.48800 %
FIGURE 5 – THD+N VS. OUTPUT POWER
VIN = 25V
fIN = 1kHz
RL = 2Ω
0.001
100
0.002
0.005
0.01
0.02
0.05
0.1
0.2
0.5
1
2
5
10
20
50
0.19402
0.02322
THD+N (%)
20 20k50 100 200 500 1k 2k 5k 10k
5.025k126.2
Frequency (Hz)
dx=-4.8988 kHz dy=-0.17080 %
FIGURE 6 – THD+N VS. FREQUENCY
VIN = 15V
RL = 4Ω
PO = 1WRMS
0.001
100
0.002
0.005
0.01
0.02
0.05
0.1
0.2
0.5
1
2
5
10
20
50
0.1798
0.06044
THD+N (%)
20 20k50 100 200 500 1k 2k 5k 10k
5.025k126.2
Frequency (Hz)
dx=-4.8988 kHz dy=-0.11937 %
FIGURE 7 – THD+N VS. FREQUENCY
VIN = 25V
RL = 4Ω
PO = 1WRMS
G
GR
RA
AP
PH
HS
S
Microsemi
Linfinity Microelectronics Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 10
Copyright © 2001
Rev. 1.2a,2004-06-10
WWW.Microsemi .COM
AudioMAX™ LX1721 / 1722
Class-D Stereo Power Amplifier Controller
P
RODUCTION
INTEGRATED PRODUCTS
CHARACTERISTIC CURVES (CONTINUED)
-10
+10
-8
-6
-4
-2
+0
+2
+4
+6
+8
-0.965
-1.119
Voltage Amplification (dBr)
10 80k20 50 100 200 500 1k 2k 5k 10k 20k 50k
17.8875k18.2
Frequency (Hz)
dx=-17.869 kHz dy=-0.155 dB
FIGURE 8 – FREQUENCY RESPONSE
VIN = 15V
RL = 4Ω
PO = 1WRMS
-10
+10
-8
-6
-4
-2
+0
+2
+4
+6
+8
-1.606
-1.436
Voltage Amplification (dBr)
10 80k20 50 100 200 500 1k 2k 5k 10k 20k 50k
17.8875k18.2
Frequency (Hz)
dx=-17.869 kHz dy=+0.170 dB
FIGURE 9 – FREQUENCY RESPONSE
VIN = 25V
RL = 4Ω
PO = 1WRMS
-150
+10
-140
-130
-120
-110
-100
-90
-80
-70
-60
-50
-40
-30
-20
-10
+0
-98.12
-94.916
dBV
20 20k50 100 200 500 1k 2k 5k 10k
3.96192k.973932k
Frequency (Hz)
dx=-2.9880 kHz dy=+3.205 dB
FIGURE 10 – NOISE FLOOR FFT
VIN = 15V
RL = 4Ω
10Hz – 22kHz Bandwidth
A-weighted
G
GR
RA
AP
PH
HS
S
Microsemi
Linfinity Microelectronics Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 11
Copyright © 2001
Rev. 1.2a,2004-06-10
WWW.Microsemi .COM
AudioMAX™ LX1721 / 1722
Class-D Stereo Power Amplifier Controller
P
RODUCTION
INTEGRATED PRODUCTS
CHARACTERISTIC CURVES (CONTINUED)
-150
+10
-140
-130
-120
-110
-100
-90
-80
-70
-60
-50
-40
-30
-20
-10
+0
-94.11
-96.079
dBV
20 20k50 100 200 500 1k 2k 5k 10k
3.96192k.973932k
Frequency (Hz)
dx=-2.9880 kHz dy=-1.969 dB
FIGURE 11 – NOISE FLOOR FFT
VIN = 25V
RL = 4Ω
10Hz – 22kHz Bandwidth
A-Weighted
45%
50%
55%
60%
65%
70%
75%
80%
85%
90%
0 5 10 15 20 25 30
Output Power (W)
Efficency (%)
842
FIGURE 12 – EFFICIENCY VS. OUTPUT
POWER
VIN = 15V
fIN = 1kHz
Power Supply Rejecti on Rat io ( P S RR)
-100
-90
-80
-70
-60
-50
-40
-30
-20
-10
0
10 100 1000 10000 100000
Frequency (Hz)
Amplitude (dB)
15V+1,Left 15V+1,Right 15V-1,Left 15V-1,Right
FIGURE 13 – POWER SUPPLY REJECTION
RATIO (PSSR)
PO = 1WRMS
RL = 4Ω
G
GR
RA
AP
PH
HS
S
Microsemi
Linfinity Microelectronics Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 12
Copyright © 2001
Rev. 1.2a,2004-06-10
WWW.Microsemi .COM
AudioMAX™ LX1721 / 1722
Class-D Stereo Power Amplifier Controller
P
RODUCTION
INTEGRATED PRODUCTS
APPLICATION
RFBK+
Vcc
R13
5.1/1W
Q5
C34
0.47uF/50V
C7 100pF
R10
5.1/1W
U1
LX1721-01CDB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22 23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
LFAOUT
CPWM
RPWM
_LMUTE
LEAOUT
LEAIN
VREF
CLOCK
GND
V25
LIN+
LIN-
LAMPOUT
RIN+
RIN-
RAMPOUT
SLEEP
STATUS
_RMUTE
REAIN
REAOUT
RFAOUT RFBK-
RFBK+
RISN
NC
PVDD
CP
PGND
RN+
RP+
RP-
RN-
LN-
LP-
LP+
LN+
PGND
PVDD
CN
VDD
LISN
LFBK+
LFBK-
R14
5.1/1W
R1 10k
+
C15
10uF/25V
+
C21
47uF/25V
Vcc
R4 56.2k 1%
L1
15uH
RISN
C33
0.68uF/50V
RISN
RFBK-
+C1
1000µF
25V
C31
0.47uF/50V
Q3
LFBK-
C30
0.68uF/50V
OUTR+
PGND
C27
220pF
R8
5.1/1W
Vcc
RN-
L4
15uH
LN+
C14 0.1uF/25V
JP1
Teminal 2
1
2
C10 150pF
C28
220pF
LN-
LIN+
OUTL+
C2
0.1uF/25V
C19
0.1uF/25V
L2
15uH
C29
0.68uF/50V
OUTR-
PGND
C12150pF
PGND
R11
5.1/1W
Q6
+
C20 4.7uF/25V,TANT
C3 0.47uF
R6
0.020/1W
R17
24.3K 1%
RFBK-
Vcc
RFBK+
RP+
Vcc
Vcc
C16
0.1uF/25V
R15
5.1/1W
LFBK+
R20
15/1W
R21
15/1W
R2 56.2k 1%
R16
24.3K 1%
C5 0.47uF
Vcc
R3 10k
Q7
C9 18pF
C6 0.47uF
PGND
RN+
RIN-
LIN-
+
C17 4.7uF/25V,TANT
Vcc
+C18
47uF/25V
Q8
Vcc
GND
C32
0.68uF/50V
C25
220pF
RIN+
_MUTE
R12
5.1/1W
GND
LFBK-
R9
5.1/1W
Vcc
R7
0.020/1W
LISN
LIN+
RIN-
C11 18pF
LIN-
C26
220pF
PGND
C22
0.1uF/25V
RP-
+
C13 1uF/10V,TANT
R19
24.3K 1%
LFBK+
L3
15uH
PGND
R5 34.8k 1%
SLEEP
Q2
LISN
R18
24.3K 1%
RIN+
LP-
PGND
LP+
Q1
C4 0.47uF
PGND
Q4
OUTL-
FIGURE 14 – TYPICAL CLASS-D STEREO SWITCHING AMPLIFIER CIRCUIT APPLICATION
A
AP
PP
PL
LI
IC
CA
AT
TI
IO
ON
N
Microsemi
Linfinity Microelectronics Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 13
Copyright © 2001
Rev. 1.2a,2004-06-10
WWW.Microsemi .COM
AudioMAX™ LX1721 / 1722
Class-D Stereo Power Amplifier Controller
P
RODUCTION
INTEGRATED PRODUCTS
MECHANICAL DIMENSIONS
DB 44-Pin Quarter Size Outline Package (QSOP)
G
E
D
A
C
M
EP
BF
L
ZD
122
23
44
R
MILLIMETERS INCHES
Dim MIN MAX MIN MAX
A 2.44 2.64 0.096 0.104
B 0.28 0.51 0.011 0.020
C 0.23 0.32 0.091 0.0125
D 17.73 17.93 0.698 0.706
E 7.40 7.60 0.291 0.299
F 0.80 BSC 0.0315 BSC
G 0.10 0.30 0.004 0.012
L 0.40 1.27 0.016 0.050
M 0° 8° 0° 8°
P 10.11 10.51 0.396 0.414
R 0.63 0.89 0.025 0.035
ZD 0.51 REF 0.020 REF
*LC - 0.10 - 0.004
* Lead Coplanarity
Note: Dimensions do not include mold flash or protrusions; these shall not exceed 0.15mm (.006”) on any side. Lead dimension shall not include
solder coverage.
M
ME
EC
CH
HA
AN
NI
IC
CA
AL
LS
S
Microsemi
Linfinity Microelectronics Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 14
Copyright © 2001
Rev. 1.2a,2004-06-10
WWW.Microsemi .COM
AudioMAX™ LX1721 / 1722
Class-D Stereo Power Amplifier Controller
P
RODUCTION
INTEGRATED PRODUCTS
NOTES
PRODUCTION DATA – Information contained in this document is proprietary to Microsemi and
is current as of publication date. This document may not be modified in any way without the
express written consent of Microsemi. Product processing does not necessarily include testing of
all parameters. Microsemi reserves the right to change the configuration and performance of the
product and to discontinue product at any time.
N
NO
OT
TE
ES
S
