SI4831-B30 Datasheet, PDF (11/20 Pages) Silicon Laboratories – BROADCAST MECHANICAL TUNING AM/FM/SW RADIO RECEIVER

Si4831/35-B30
The stereo light up criteria is defined using both RSSI
and the Left and Right separation levels as these two
specifications are the primary factors for stereo
listening. The criteria can be set between two
conditions: the Left and Right channels are separated
by more than 6 dB with RSSI at >20 dB or Left and
Right channels are separated by more than 12 dB with
RSSI at >28 dB. The selection can be set up using
different values of the external resister. Refer to
"AN555: Si483x-B Antenna, Schematic, Layout, and
Design Guidelines."
4.3. AM Receiver
The highly integrated Si4831/35-B30 supports
worldwide AM band reception from 504 to 1750 kHz
with five sub-bands using a digital low-IF architecture
with a minimum number of external components and no
manual alignment required. This patented architecture
allows for high-precision filtering, offering excellent
selectivity and SNR with minimum variation across the
AM band. Similar to the FM receiver, the Si4831/35-B30
optimizes sensitivity and rejection of strong interferers,
allowing better reception of weak stations.
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.
4.4. SW Receiver
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.
4.5. Frequency Tuning
A valid channel can be found by tuning the
potentiometer that is connected to the TUNE1 and
TUNE2 pin of the Si4831/35-B30 chip.
To offer easy tuning, the Si4831/35-B30 also supports a
station LED light. It will light up the LED if the RF signal
quality passes the LED sensitivity threshold when tuned
to a valid station.
4.6. Band Select
The Si4831/35-B30 supports worldwide AM band with
five sub-bands, US/Europe/Japan/China FM band with
five sub-bands, and SW band with 16 sub-bands. For
details on band selection, refer to "AN555: Si483x-B
Antenna, Schematic, Layout, and Design Guidelines."
4.7. Bass and Treble
The Si4831/35-B30 further supports bass and treble
tone control for superior sound quality. Pins 16 and 17
can be configured for tone control, allowing customers
to use either two buttons or one slide-switch to adjust
the bass and treble. For further configuration details,
refer to "AN555: Si483x-B Antenna, Schematic, Layout,
and Design Guidelines."
4.8. Volume Control
The Si4831/35-B30 not only allows customers to use
the traditional PVR wheel volume control through an
external speaker amplifier, it also supports direct digital
volume control through pins 16 and pin 17 by using
volume up and down buttons. Refer to "AN555: Si483x-
B Antenna, Schematic, Layout, and Design Guidelines."
Rev. 1.0
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