Si4730/31/34/35-D60
optimize sensitivity and rejection of strong interferers
allowing better reception of weak stations.
4.2. Operating Modes
The Si473x-D60 operates in either an FM receive, AM
receive, or audio AUXIN ADC mode. In FM mode, radio
signals are received on FMI and processed by the FM
front-end circuitry. In AM mode, radio signals are
received on AMI and processed by the AM front-end
circuitry. In audio AUXIN ADC mode, stereo audio
signals on LIN/RIN are sampled, converted to digital,
The Si473x-D60 provides highly-accurate digital AM
tuning without factory adjustments. To offer maximum
flexibility, the receiver supports a wide range of ferrite
loop sticks from 180–450 µH. An air loop antenna is
supported by using a transformer to increase the
effective inductance from the air loop. Using a 1:5 turn
ratio inductor, the inductance is increased by 25 times
and easily supports all typical AM air loop antennas
which generally vary between 10 and 20 µH.
2
filtered, and decimated to 32, 44.1, or 48 kHz for the I S
digital audio interface. In addition to the receiver mode,
there is a clocking mode to choose to clock the Si473x-
D60 from a reference clock or crystal. On the Si473x-
D60, there is an audio output mode to choose between
an analog and/or digital audio output. In the analog
audio output mode, ROUT and LOUT are used for the
audio output pins. In the digital audio mode, DOUT,
DFS, and DCLK pins are used. Concurrent
analog/digital audio output mode is also available
requiring all five pins.
4.5. SW Receiver
The Si4734/35 is the first fully integrated IC to support
AM and FM, as well as short wave (SW) band reception
from 2.3 to 26.1 MHz fully covering the 120 meter to
11 meter bands. The Si4734/35 offers extensive
shortwave features such as continuous digital tuning
with minimal discrete components and no factory
adjustments. Other SW features include adjustable
channel step sizes in 1 kHz increments, adjustable
channel bandwidth settings, advanced seek algorithm,
and soft mute.
4.3. FM Receiver
The Si473x-D60 FM receiver is based on the proven
Si4700/01 FM tuner. The receiver uses a digital low-IF
architecture allowing the elimination of external The Si4734/35 uses the FM antenna to capture short
components and factory adjustments. The Si473x-D60 wave signals. These signals are then fed directly into
integrates a low noise amplifier (LNA) supporting the the AMI pin in a wide band configuration. See "AN332:
worldwide FM broadcast band (64 to 108 MHz). An Si47xx Programming Guide” and “AN383: Si47xx
AGC circuit controls the gain of the LNA to optimize Antenna and Schematic Guidelines" for more details.
sensitivity and rejection of strong interferers. An image-
4.6. LW Receiver
reject mixer downconverts the RF signal to low-IF. The
quadrature mixer output is amplified, filtered, and The Si4734/35 supports the long wave (LW) band from
digitized with high resolution analog-to-digital 153 to 279 kHz. The highly integrated Si4734/35 offers
converters (ADCs). This advanced architecture allows continuous digital tuning with minimal discrete
the Si473x-D60 to perform channel selection, FM components and no factory adjustments. The Si4734/35
demodulation, and stereo audio processing to achieve also offers adjustable channel step sizes in 1 kHz
superior performance compared to traditional analog increments, adjustable channel bandwidth settings,
architectures.
advanced seek algorithm, and soft mute.
The Si4734/35 uses a separate ferrite bar antenna to
capture long wave signals.
4.4. AM Receiver
The highly-integrated Si473x-D60 supports worldwide
AM band reception from 520 to 1710 kHz using a digital
low-IF architecture with a minimum number of external
components and no manual alignment required. This
digital low-IF architecture allows for high-precision
filtering offering excellent selectivity and SNR with
minimum variation across the AM band. The DSP also
provides adjustable channel step sizes in 1 kHz
increments, AM demodulation, soft mute, seven
different channel bandwidth filters, and additional
features, such as a programmable automatic volume
control (AVC) maximum gain allowing users to adjust
the level of background noise.
4.7. Stereo Audio AUXIN ADC
The Si473x-D60 stereo audio AUXIN ADC can be
multiplexed between low-IF input for radio operation
and analog audio input for high fidelity data conversion
at 32, 44.1, or 48 kHz sample rate. When operated in
ADC-mode, the Si473x-D60 supports I2S digital audio
output only (no analog output) while enabling the analog
inputs and the stereo ADC.
Similar to the FM receiver, the integrated LNA and AGC
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Rev. 1.1
SILICON [ SILICON ]
