Si4730/31
Broadcast AM/FM Radio Receiver
Description
The Si4730/31 is the industry's first fully integrated, 100%
CMOS AM/FM radio receiver IC. The Si4730/31 AM/FM
radio provides the space savings and low power
consumption necessary for portable devices while
delivering the high performance and design simplicity
desired for all AM/FM solutions. Offering unmatched
integration and PCB space savings, the Si4730/31
requires only two external components and less than 15
mm
2
of board area.
Leveraging Silicon Laboratories' proven and patented
Si4700/01 FM digital receiver architecture, the Si4730/31
delivers superior RF performance and interference
rejection in both AM and FM bands. The high integration
and complete system production test simplifies design-in,
increases system quality, and improves manufacturability.
The Si4730/31 solution includes advanced seek
algorithms, adjustable soft mute, auto-calibrated digital
tuning, and FM stereo processing. In addition, the Si4730/
31 provides a programmable reference clock, I
2
C-
compatible 2-wire control interface, and a Si4700/01
backwards-compatible 3-wire control interface.
The Si4730/31 utilizes digital processing to achieve high
fidelity, optimal performance, and design flexibility. The
chip provides excellent pilot rejection, selectivity, and
unmatched audio performance, and offers both the
manufacturer and the end-user extensive programmability
and flexibility in listening experience.
The Si4731 incorporates a digital processor for the
European Radio Data System (RDS) and the North
American Radio Broadcast Data System (RBDS)
including all required symbol decoding, block
synchronization, error detection, and error correction
functions. Using this feature, the Si4731 enables
broadcast data such as station identification and song
name to be displayed to the end user.
Features
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Worldwide FM band support (76–108 MHz)
Worldwide AM band support (520–1710 kHz)
AM/FM digital tuning
Excellent real-world performance
Only 2 external components
No manual alignment required
Adjustable AM channel filters
Advanced AM/FM seek tuning
Digital volume control
Adjustable soft mute control
Frequency synthesizer with integrated VCO
Automatic frequency control (AFC)
Automatic gain control (AGC)
Programmable AM/FM de-emphasis
Adaptive noise suppression
Integrated LDO regulator
Programmable reference clock
FM RDS/RBDS processor (Si4731 only)
2-wire and 3-wire control interface
2.7 to 5.5 V supply voltage
AM ferrite loopstick and air loop antenna support
3 x 3 x 0.55 mm 20-pin QFN package
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Pb-free/RoHS compliant
Table and portable radios
Stereos
Mini/micro systems
Portable media players
Boomboxes
Cellular handsets
Clock radios
Modules
Entertainment systems
Applications
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Si473x
AMI
AM
ANT
RFGND
LNA
AGC
ADC
FMI
LNA
AGC
2.7–5.5 V
VDD
GND
LDO
AFC
ADC
DSP
DAC
LOUT
RDS
(Si4731)
LOW-IF
DAC
ROUT
FM
ANT
CONTROL
INTERFACE
VIO
1.5–3.6 V
SDIO
AM/FM Receiver
Copyright © 2007 by Silicon Laboratories
RCLK
SCLK
SEN
RST
6.15.07
Si4730/31
Broadcast AM/FM Radio Receiver
Selected FM Electrical Specifications
Parameter
Symbol
Input Frequency
f
RF
Sensitivity headphone matching
Sensitivity 50
Ω
matching
Input IP3
Adjacent Channel Selectivity
Alternate Channel Selectivity
Audio Band Limits
Audio S/N
Audio THD
Audio Output Voltage
Supply Voltage*
V
D
, V
A
Interface Supply Voltage*
V
IO
Powerdown Current*
I
PD
*Note:
Applies to both FM and AM modes.
Test Condition
(S+N)/N = 26 dB
(S+N)/N = 26 dB
|f
2
– f
1
| > 1 MHz; f
0
= 2 x f
1
– f
2
±200 kHz
±400 kHz
±1.5 dB
Min
76
—
—
—
—
—
30
—
—
72
2.7
1.5
—
Typ
—
2.2
1.1
105
50
70
—
63
0.1
80
—
—
10
Max
108
—
—
—
—
—
15k
—
—
90
5.5
3.6
—
Unit
MHz
µV EMF
µV EMF
dBµV EMF
dB
dB
Hz
dB
%
mVrms
V
V
µA
Selected AM Electrical Specifications
Parameter
Input Frequency
Sensitivity
Audio S/N
Audio THD
Audio Output Voltage
Antenna Inductance
Symbol
f
RF
Test Condition
(S+N)/N = 26 dB
Min
520
—
—
—
54
180
Typ
—
38
58
0.1
60
—
Max
1710
—
—
—
66
600
Unit
kHz
µV EMF
dB
%
mVrms
µH
Pin Assignments
GPO2/INT
GPO1
GPO3
3 x 3 x 0.55 mm, 20-pin QFN Package Information
NC
NC
1
20 19 18 17 16
15 NC
FMI 2
RFGND 3
AMI 4
RST 5
6
SEN
7
SCLK
8
SDIO
9
RCLK
GND
PAD
10 11 VDD
VIO
NC
14 LOUT
13 ROUT
12 GND
Symbol
Min
A
A1
b
c
D
D2
e
E
E2
0.50
0.00
0.18
0.27
1.60
Millimeters
Nom
0.55
0.02
0.25
0.32
3.00 BSC
1.70
0.50 BSC
3.00 BSC
1.70
Max
0.60
0.05
0.30
0.37
1.80
Symbol
Min
f
L
L1
aaa
bbb
ccc
ddd
eee
0.35
0.00
—
—
—
—
—
Millimeters
Nom
2.53 BSC
0.40
—
—
—
—
—
—
Max
0.45
0.10
0.10
0.10
0.08
0.10
0.10
1.60
1.80
AM/FM Receiver
Copyright © 2007 by Silicon Laboratories
6.15.07
Silicon Laboratories and Silicon Labs are trademarks of Silicon Laboratories Inc.
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