AM/FM Receiver Copyright © 2008 by Silicon Laboratories 10.23.08
ADC
ADC
Si474x
DSP
DAC
DAC
AMI
VIO
SCLK
SDIO
CNTRL
SEN
RST
ROUT
LOUT
LDO
VDD
GND
3.0–3.6 V
RDS
GND
FMI
LNA
LNA DIGITAL
AUDIO
DOUT
DFS
DCLK
AGC
AGC
AFC
RCLK
WEAK
SIGNAL
CONDITION
QUALITY
DETECTOR
AGC GPO1-3
Si4740/41/42/43/44/45
Automotive AM/FM Radio Receiver
Description
The Si474x receiver family applies 100% RF CMOS
technology to bring digital low-IF radio technology to the
automotive receiver market. The Si474x receiver family
builds on Silicon Laboratories’ hi ghly successful broadcast
audio radio products, offering design simplicity, unmatched
integration, programmability, and automotive quality and
reliability.
The Si474x receiver family supports world-wide FM bands
from 64–108 MHz and AM band s from 520–17 10 kHz. The
Si474x supports AM/FM, weather band, shortwave, and
longwave radio bands. All odd-numbered part numbers in
the family support international RDS/RBDS protocols.
The Si474x family levera ges Silico n Laboratories’ patente d
digital architecture, delivering superior RF performance
and interference rejection. The proven digital radio
technology provides excellent sensitivity in weak signal
environments, and superb selectivity and inter-modulation
immunity in strong signal environments.
The solution offers programmable AM/FM channel spacing
and filters, auto-calibrated digital tuning, and proven
AM/FM seek functionality based on multiple signal quality
and band parameters. The family offers highly flexible and
advanced audio features such as noise blanking,
programmable soft mute, and multi-path detection and
mitigation.
The Si474x receiver system has a minimal bil l of materials
requiring a small a mount of board space. The high level of
integration provides a complete, tested broadcast audio
receiver that is ideal for primary automotive radio receivers.
Features
-Worldwide FM band support (64–108 MHz)
-Worldwide AM band support (520–1710 kHz)
-Shortwave, longwave support (Si4742/43/44/45 only)
-Weather band support (Si4742/43 only)
-Received signal quality indicators (RSSI, SNR, adjacent
channel, wideband AM)
-Multip ath detection/mitiga ti o n
-AM and FM noise blankers (Si4742/43/44/45 only)
-AM and FM programmable seek tuning
-AM and FM programmable soft mute control
-AM and FM adjustable channel bandwidth filters
-FM stereo-mono blending
-FM Hi-Cut control (Si4742/43/44/45 only)
-Digital FM stereo decoder
-RDS/RBDS processor (Si4741/43/45 only)
-Automatic frequency control (AFC)
-Automatic gain control (AGC)
-Image rejection mixer
-Frequency synthesizer with integrated VCO
-Low-IF direct conversion with no ceramic filters
-Analog or digital (I2S) outputs
-3.0 to 3.6 V supply voltage
-Programmable reference clock
-AECQ-100 certified
•–40 to 85 ºC operation
- 24-pin 4 x 4 mm QFN package
•Pb-free/RoHS compliant
Applications
-OEM automotive radio systems
-After-market automotive radio systems
-Automotive radio modules
AM/FM Receiver Copyright © 2008 by Silicon Laboratories 10.23.08
Silicon Laboratories and Silicon Labs are trademarks of Silicon Laboratories Inc.
Other products or brandnames mentioned herein are trademarks or registered trademarks of their respective holders.
Si4740/41/42/43/44/45
Automotive AM/FM Radio Receiver
Selected Electrical Specifications1
(VDD = 2.7 to 5.5 V, VIO = 1.5 to 3.6 V, TA = –40 to 85 °C)
Parameter Test Condition Min Typ Max Unit
FM
Input Frequency 64 —108 MHz
Sensitivity (S+N)/N = 26 dB — 2 — µV EMF
RDS Sensitivity f = 2 kHz, RDS BLER < 5% — 8 — µV EMF
Audio S/N (Mono)2,3 fMOD = 1 kHz, f = 22.5 kHz,
VEMF = 60 dBµVEMF —63 —dB
Audio THD (Mono)2,3 fMOD = 1 kHz, f = 75 kHz,
VEMF = 60 dBµVEMF —0.1 — %
Input IP3 f1 = 4000 kHz; f2 = 8000 kHz —105 —dBµV EMF
Audio Output Voltage —80 —mVrms
Adjacent Channel Selectivity ±200 kHz —50 —dB
Alternate Channel Selectivity ±400 kHz —70 —dB
AM Suppression4m = 0.3; f = 22.5 kHz; fRF = 76 to 108 MHz;
Measured at VEMF = 60 dBµVEMF —55 —dB
Audio Stereo Separation4fRF = 76 to 108 MHz; Measured at VEMF =
60 dBµVEMF; f = 75 kHz —45 —dB
Supply Voltage53 — 3.6 V
Supply Current5—26 —mA
AM
Input Frequency 520 — 1710 kHz
Sensitivity (S+N)/N = 26 dB — 28 — µV EMF
Audio S/N4,6 30% modulation, fMOD =1 kHz,
RF level = 74 dBµV EMF; f = 22.5 kHz — 53 — dB
Audio THD4,6 30% modulation, fMOD =1 kHz,
RF level = 74 dBµV EMF; f = 22.5 kHz — 0.3 — %
Input IP37f1 = 40 kHz; f2 = 80 kHz — 112 — dBµV
Audio Output Voltage454 60 66 mVrms
Adjacent Channel Selectivity ±10 kHz — 40 — dB
Alternate Channel Selectivity ±20 kHz — 60 — dB
Notes:
1. Specifications refer to Si474x application circuit input.
2. BAF = 300 Hz to 15 kHz.
3. fRF = 76 to 108 MHz.
4. FMOD = 1 kHz, 75 µs de-emphasis, MONO = enabled, and L = R unless noted otherw ise.
5. Applies to both FM and AM modes.
6. AGC is disabled.
7. Specification refers to Si474x input.
Pin Assignments
GND
PAD
1
2
3
21222324
14
15
16
17
78910
4
5
20
13
11
19
18
12
6
NC
RCLK
DFS
DOUT
LOUT
ROUT
AMI
FMI
NC
SDIO
SCLK
GND
RFGND
AGC1
GPO1/AGC2
VDD
NC
NC
GPO2/INT
GND
VIO
SEN
RST
GPO3/DCLK
Symbol Millimeters
Min Nom Max
A 0.80 0.85 0.90
A1 0.00 0.02 0.05
b 0.18 0.25 0.30
D 4.00 BSC
D2 2.00 2.10 2.20
e 0.50 BSC
E 4.00 BSC
E2 2.00 2.10 2.20
L 0.30 0.40 0.50
aaa — — 0.10
bbb — — 0.10
ccc — — 0.08
ddd — — 0.10
eee — — 0.10
4x4x0.85mm 24-pin QFN Package Information
