SI4836-A10 Datasheet, PDF (12/21 Pages) Silicon Laboratories – BROADCAST MECHANICAL TUNING AM/FM/SW RADIO RECEIVER

Si4836-A10
discern the signal quality.
The stereo light up criteria are 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 they 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 "AN738: Si4825/36-A
Antenna, Schematic, Layout, and Design Guidelines.”
4.3. AM Receiver
The highly integrated Si4836-A10 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.
The Si4836 supports the worldwide AM band with five
sub-bands. One of the bands is a universal AM band
(AM4, 520–1730 kHz) supporting both 9 kHz and
10 kHz channel spaces for all regional AM standards of
the world. Similar to the FM receiver, the Si4836
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 Si4836 supports 36 short wave (SW) band
receptions from 2.3 to 28.5 MHz, 18 of which are meter
wave band (Narrow), and the rest of the SW bands are
with wider frequency range that can be used in SW
radio with 1 or 2 SW bands. Si4836 supports extensive
short wave features such as minimal discrete
components and no factory adjustments. The Si4836
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 Si4836 chip.
To offer easy tuning, the Si4836 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 Si4836 supports worldwide AM band with five sub-
bands, US/Europe/Japan/China FM band with five sub-
bands, and SW band with 36 sub-bands. For details on
band selection, refer to “AN738: Si4825/36-A Antenna,
Schematic, Layout, and Design Guidelines."
4.7. Bass and Treble
The Si4836 further supports bass and treble tone
control for superior sound quality. Pins 12 can be
configured for tone control with single push button if the
system can provide 32.768 kHz external clock to Pin13,
allowing customers to adjust the bass and treble in a
cyclic way. For further configuration details, refer to
"AN738: Si4825/36-A Antenna, Schematic, Layout, and
Design Guidelines."
4.8. Reset, Powerup, and Powerdown
Setting the RSTB pin low will disable analog and digital
circuitry, reset the registers to their default settings, and
disable the bus. Setting the RSTB pin high will bring the
device out of reset.
Figure 1 shows typical reset, startup, and shutdown
timings for the Si4836. RSTB must be held low
(asserted) during any power supply transitions and kept
asserted as specified in Figure 1 after the power
supplies are ramped up and stable. Failure to assert
RSTB as indicated here may cause the device to
malfunction and may result in permanent device
damage.
A powerdown mode is available to reduce power
consumption when the part is idle. Putting the device in
powerdown mode will disable analog and digital circuitry
while keeping the bus active.
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Rev. 1.0