B M T Am/Fm/Sw R R: Roadcast Echanical Uning Adio Eceiver
B M T Am/Fm/Sw R R: Roadcast Echanical Uning Adio Eceiver
B R O A D C A S T M E C H A N I C A L TU N I N G A M / F M / S W R A D I O R EC EIVER
Features
Worldwide FM band support Automatic frequency control (AFC)
(64–109 MHz) Integrated LDO regulator
Worldwide AM band support 2.0 to 3.6 V supply voltage
(504–1750 kHz) Wide range of ferrite loop sticks and air
SW band support (Si4835 only) loop antennas supported
(5.6–22 MHz) 24-pin SSOP
Excellent real-world performance RoHS-compliant
EN55020-compliant Supports station and stereo LED
No manual alignment necessary indicators
Flexible band selections Ordering Information:
Direct volume control
See page 13.
Bass and treble tone control
Applications
Pin Assignments
Table and portable radios Modules
Stereos Clock radios
Mini/micro systems Mini HiFi Si4831/35-B30 (SSOP)
CD/DVD players Entertainment systems
Boom boxes STEREO 1 24 LOUT
STATION 2 23 ROUT
Description TUNE1 3 22 DBYP
TUNE2 4 21 VDD2
The Si4831/35-B30 is the 2nd generation mechanical-tuned digital CMOS BAND 5 20 VDD1
AM/FM/SW radio receiver IC that integrates the complete receiver function from NC 6 19 XTALI
antenna input to audio output. Like other successful audio products from Silicon NC 7 18 XTALO
Labs, Si4831/35-B30 offers unmatched integration and PCB space savings with FMI 8 17 VOL-/BASS
minimum external components and a small board area. The Si4831/35-B30 RFGND 9 16 VOL+/TREBLE
requires a simple application circuit and removes any requirements for manually NC 10 15 RST
lines. The receiver has very low power consumption, runs off two AAA batteries,
and delivers the performance benefits of digital tuning to the analog radio market.
Functional Block Diagram This product, its features, and/or its
architecture is covered by one or more of
Si4831/35 the following patents, as well as other
Si4830/34 patents, pending and issued, both
AMI ADC DAC LOUT foreign and domestic: 7,127,217;
AM
LNA DSP 7,272,373; 7,272,375; 7,321,324;
ANT RFGND
ADC DAC
7,355,476; 7,426,376; 7,471,940;
ROUT
FM/SW 7,339,503; 7,339,504.
ANT AGC
FMI
0/90
TUNE 1/2
ADC
2 Rev. 1.0
Si4831/35-B30
TABLE O F C ONTENTS
Section Page
1. Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
2. Typical Application Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
3. Bill of Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
4. Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
4.1. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
4.2. FM Receiver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
4.3. AM Receiver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
4.4. SW Receiver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
4.5. Frequency Tuning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
4.6. Band Select . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
4.7. Bass and Treble . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
4.8. Volume Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
5. Pin Descriptions: Si4831/35-B30 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
6. Ordering Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
7. Package Markings (Top Marks) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
7.1. Si4831/35-B30 Top Mark . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
7.2. Top Mark Explanation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
8. Package Outline: Si4831/35-B30 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
9. PCB Land Pattern: Si4831/35-B30 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
10. Additional Reference Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Document Change List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
Contact Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
Rev. 1.0 3
Si4831/35-B30
1. Electrical Specifications
4 Rev. 1.0
Si4831/35-B30
Table 3. DC Characteristics
(VDD = 2.7 to 3.6 V, TA = –15 to 85 °C)
RST Pulse Width and TUNE1, TUNE2 Setup to RST tSRST 100 — — µs
tSRST tHRST
70%
RST
30%
70%
TUNE1
30%
70%
TUNE2
30%
Rev. 1.0 5
Si4831/35-B30
AM Suppression4,5,6,7 m = 0.3 — 50 — dB
Input IP34,8 — 105 — dBµV EMF
6 Rev. 1.0
Si4831/35-B30
Audio S/N3,4,6 — 55 — dB
Notes:
1. Additional testing information is available in “AN569: Si4831/35-DEMO Board Test Procedure.” Volume = maximum
for all tests. Tested at RF = 520 kHz.
2. To ensure proper operation and receiver performance, follow the guidelines in “AN555: Si483x-B Antenna, Schematic,
Layout, and Design Guidelines.” Silicon Laboratories will evaluate schematics and layouts for qualified customers.
3. FMOD = 1 kHz, 30% modulation, 2 kHz channel filter.
4. BAF = 300 Hz to 15 kHz, A-weighted.
5. Guaranteed by characterization.
6. VIN = 5 mVrms.
7. Stray capacitance on antenna and board must be < 10 pF to achieve full tuning range at higher inductance levels.
Rev. 1.0 7
Si4831/35-B30
2. Typical Application Schematic
FMI TUNE1
TUNE1
R3
2.5k/100M
253k
S2
(Si4835 only) VR1
B1
100k
BAND 1 2
AM
3
AM antenna
R2 R4
VDD
ANT1
180k
10k
C5
BAND
AMI STATION_LED
FM
STEREO_LED
0.47u
12
11
10
1
RFGND
BAND
STATION
AMI
TUNE2
TUNE1
NC
NC
FMI
NC
NC
STEREO
R5
67k
C5
VOL+/TREBLE
AMI U1
VOL-/BASS
0.47u
XTAL0
XTALI
ROUT
VDD1
VDD2
LOUT
ANT2
DBYP
GND
GND
RST
RFGND
13
14
15
16
17
18
19
20
21
22
23
24
T1
LOUT
C4
Optional: AM air loop antenna ROUT
0.1u
VDD
R1 2.0 TO 3.6V
VDD
VDD
2.0 TO 3.6V
100k
C1 Y1
0.1u
32.768KHz
C3 C2
22p 22p
Optional
Notes:
1. Place C4 close to VDD2 and DBYP pins.
2. All grounds connect directly to GND plane on PCB.
3. Pin 6 and 7 leave floating.
4. To ensure proper operation and receiver performance, follow the guidelines in "AN555: Si483x-B Antenna, Schematic,
Layout, and Design Guidelines." Silicon Labs will evaluate the schematics and layouts for qualified customers.
5. Pin 8 connects to the FM antenna interface and pin 12 connects to the AM antenna interface.
6. Place Si483x as close as possible to antenna jack and keep the FMI and AMI traces as short as possible.
8 Rev. 1.0
Si4831/35-B30
3. Bill of Materials
Rev. 1.0 9
Si4831/35-B30
4. Functional Description
Si4831/35
Si4830/34
AMI ADC DAC LOUT
AM
LNA DSP
ANT RFGND
ADC DAC ROUT
FM/SW
ANT AGC
FMI
0/90
TUNE 1/2
ADC
VOL/TONE
STATION
STEREO
RST
Figure 2. Si4831/35-B30 Functional Block Diagram
4.1. Overview 4.2. FM Receiver
The Si4831/35-B30 is the industry's most advanced The Si4831/35-B30 integrates a low noise amplifier
fully integrated, mechanical-tuned 100% CMOS (LNA) supporting the worldwide FM broadcast band (64
AM/FM/SW radio receiver IC. Offering unmatched to 109 MHz).
integration and PCB space savings, the Si4831/35-B30 Pre-emphasis and de-emphasis is a technique used by
requires minimum external components and a small FM broadcasters to improve the signal-to-noise ratio of
board area. The Si4831/35-B30 AM/FM/SW radio FM receivers by reducing the effects of high frequency
provides space savings and low power consumption interference and noise. When the FM signal is
while delivering the high performance and design transmitted, a pre-emphasis filter is applied to
simplicity desired for all AM/FM/SW solutions. accentuate the high audio frequencies. All FM receivers
Leveraging Silicon Laboratories' proven and patented incorporate a de-emphasis filter which attenuates high
digital low intermediate frequency (low-IF) receiver frequencies to restore a flat frequency response. Two
architecture, the Si4831/35-B30 delivers superior RF time constants are used in various regions. The de-
performance and interference rejection in AM, FM, and emphasis time constant can be chosen to be 50 or
SW bands. The high integration and complete system 75 µs. Refer to "AN555: Si483x-B Antenna, Schematic,
production test simplifies design-in, increases system Layout, and Design Guidelines."
quality, and improves manufacturability. The Si4831/35-B30 also has advanced stereo blending
that employs adaptive noise suppression. As a signal
quality degrades, the Si4831/35-B30 gradually
combines the stereo left and right audio channels to a
mono audio signal to maintain optimum sound fidelity
under varying reception conditions. The Si4831/35-B30
can drive a stereo light with the stereo/mono information
so that the user can easily discern the signal quality.
10 Rev. 1.0
Si4831/35-B30
The stereo light up criteria is defined using both RSSI 4.5. Frequency Tuning
and the Left and Right separation levels as these two
A valid channel can be found by tuning the
specifications are the primary factors for stereo
potentiometer that is connected to the TUNE1 and
listening. The criteria can be set between two
TUNE2 pin of the Si4831/35-B30 chip.
conditions: the Left and Right channels are separated
by more than 6 dB with RSSI at >20 dB or Left and To offer easy tuning, the Si4831/35-B30 also supports a
Right channels are separated by more than 12 dB with station LED light. It will light up the LED if the RF signal
RSSI at >28 dB. The selection can be set up using quality passes the LED sensitivity threshold when tuned
different values of the external resister. Refer to to a valid station.
"AN555: Si483x-B Antenna, Schematic, Layout, and 4.6. Band Select
Design Guidelines."
The Si4831/35-B30 supports worldwide AM band with
4.3. AM Receiver five sub-bands, US/Europe/Japan/China FM band with
The highly integrated Si4831/35-B30 supports five sub-bands, and SW band with 16 sub-bands. For
worldwide AM band reception from 504 to 1750 kHz details on band selection, refer to "AN555: Si483x-B
with five sub-bands using a digital low-IF architecture Antenna, Schematic, Layout, and Design Guidelines."
with a minimum number of external components and no 4.7. Bass and Treble
manual alignment required. This patented architecture
allows for high-precision filtering, offering excellent The Si4831/35-B30 further supports bass and treble
selectivity and SNR with minimum variation across the tone control for superior sound quality. Pins 16 and 17
AM band. Similar to the FM receiver, the Si4831/35-B30 can be configured for tone control, allowing customers
optimizes sensitivity and rejection of strong interferers, to use either two buttons or one slide-switch to adjust
allowing better reception of weak stations. the bass and treble. For further configuration details,
refer to "AN555: Si483x-B Antenna, Schematic, Layout,
To offer maximum flexibility, the receiver supports a
and Design Guidelines."
wide range of ferrite loop sticks from 180–450 µH. An
air loop antenna is supported by using a transformer to 4.8. Volume Control
increase the effective inductance from the air loop.
The Si4831/35-B30 not only allows customers to use
Using a 1:5 turn ratio inductor, the inductance is
the traditional PVR wheel volume control through an
increased by 25 times and easily supports all typical AM
external speaker amplifier, it also supports direct digital
air loop antennas, which generally vary between 10 and
volume control through pins 16 and pin 17 by using
20 µH.
volume up and down buttons. Refer to "AN555: Si483x-
4.4. SW Receiver B Antenna, Schematic, Layout, and Design Guidelines."
The Si4835 supports 16 short wave (SW) band
receptions from 5.60 to 22.0 MHz. Si4835 supports
extensive short wave features such as minimal discrete
components and no factory adjustments. The Si4835
supports using the FM antenna to capture short wave
signals.
Rev. 1.0 11
Si4831/35-B30
5. Pin Descriptions: Si4831/35-B30
STEREO 1 24 LOUT
STATION 2 23 ROUT
TUNE1 3 22 DBYP
TUNE2 4 21 VDD2
BAND 5 20 VDD1
NC 6 19 XTALI
NC 7 18 XTALO
FMI 8 17 VOL-/BASS
RFGND 9 16 VOL+/TREBLE
NC 10 15 RST
NC 11 14 GND
AMI 12 13 GND
12 Rev. 1.0
Si4831/35-B30
6. Ordering Guide
Rev. 1.0 13
Si4831/35-B30
7. Package Markings (Top Marks)
7.1. Si4831/35-B30 Top Mark
4831B30GU
YYWWTTTTTT
4835B30GU
YYWWTTTTTT
7.2. Top Mark Explanation
14 Rev. 1.0
Si4831/35-B30
8. Package Outline: Si4831/35-B30
The 24-pin SSOP illustrates the package details for the Si4831/35-B30. Table 9 lists the values for the dimensions
shown in the illustration.
Rev. 1.0 15
Si4831/35-B30
9. PCB Land Pattern: Si4831/35-B30
Figure 4, “PCB Land Pattern,” illustrates the PCB land pattern details for the Si4831/35-B30-GU SSOP. Table 10
lists the values for the dimensions shown in the illustration.
16 Rev. 1.0
Si4831/35-B30
10. Additional Reference Resources
Contact your local sales representatives for more information or to obtain copies of the following references:
EN55020 Compliance Test Certificate
AN555: Si483x-B Antenna, Schematic, Layout, and Design Guidelines
AN569: Si4831/35-DEMO Board Test Procedure
Si4831/35-DEMO Board User’s Guide
Rev. 1.0 17
Si4831/35-B30
DOCUMENT CHANGE LIST
Revision 0.1 to Revision 0.7
Updated block diagram.
Updated application schematic.
Updated bill of materials.
Updated Section “4.2. FM Receiver”.
Updated Section “4.3. AM Receiver”.
Updated Section “4.6. Band Select”.
Revision 0.7 to Revision 1.0
Updated block diagram
Updated Table 2, “Absolute Maximum Ratings1,2,”
on page 4
Updated Table 5, “FM Receiver Characteristics1,2,”
on page 6
Updated Table 6, “AM/SW Receiver Characteristics1,
2
,” on page 7
Updated “4. Functional Description”
Updated “10. Additional Reference Resources”
18 Rev. 1.0
Si4831/35-B30
NOTES:
Rev. 1.0 19
Smart.
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