TSH511CF STMicroelectronics, TSH511CF Datasheet - Page 20

• Manufacturer Part Number: TSH511CF
• Description: IC RECEIVER DUAL FM 44-TQFP
• Manufacturer: STMicroelectronics

Specifications of TSH511CF

• Frequency: 2.3MHz and 2.8MHz
• Sensitivity: -95dBm
• Modulation Or Protocol: FM
• Applications: Infrared Headsets, Infrared Hi-Fi Stereo Transmitters
• Current - Receiving: 15mA
• Data Interface: PCB, Surface Mount
• Antenna Connector: PCB, Surface Mount
• Voltage - Supply: 2.3 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 44-TQFP, 44-VQFP
• For Use With: 497-8516 - BLANK PCB W/ BOM FOR TSH511/12
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Features: -
• Memory Size: -
• Data Rate - Maximum: -
• Other names: 497-2322

General description
8.4
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The low output impedance of the demodulator (MIX-OUT pins) drives the external volume
control and the de-emphasis filter.
Figure 28. FM demodulator schematics
Squelch section
To avoid audio FM noise at the speakers when no carrier is received, the TSH511 has a
built-in squelch circuit. The squelch detects the wideband FM noise on the demodulated
output and fades out the audio of both audio buffers.
The audio is filtered from the FM noise using the high-pass RC filter. The cut-off frequency is
typically 100kHz. The squelch level depends on the value of the R
with the input pin of the noise amplifier MUTE-IN (pin 23). The detected noise is integrated
with the C
amplitude of the noise.
The comparator and the C
for the audio buffers. The squelch was designed with particular attention to avoid audio pop-
noise.
peak
capacitor connected to MUTE-INT pin. The DC voltage on this pin follows the
MUTE
capacitor generate the fade-in and fade-out control ramps
MUTE
resistor in series
TSH511