TSH511CF STMicroelectronics, TSH511CF Datasheet - Page 19

• 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

TSH511
8.2
8.3
The LNA output is directly connected to LNA-OUT1 and LNA-OUT2 pins in parallel (pin 8
and 4 respectively). Because the LNA minimum impedance load is 1k
on each pin LNA-OUT1 or LNA-OUT2 must be 2k
The series 50
thus improving noise performance.
AMP and LIM sections: amplifier and limiter
The first filter output is connected to the intermediate amplifier AMP. The gain of AMP is
typically 20dB. The second filter is connected between the output of AMP and the input of
the limiter LIM. The 60dB limiter LIM provides a constant amplitude signal to the FM
demodulator. It reduces the AM parasitic effects into the FM demodulator.
Figure 27. AMP and LIM schematics
FM demodulator section
The FM demodulator is a classic quadrature demodulator based on a multiplier. The
quadrature is performed with the tank circuit L
is tuned on the receiving frequency.
The R
circuit. It allows to adjust the demodulation characteristics. For a given transmitting
deviation, a lower value of R
distortion.
The AC amplitude on pin 18 must not exceed 300mV
ESD diodes of the circuit.
lo
resistor is connected in parallel with L
Ω
resistor and the 100nF capacitor decouple the LNA supply voltage (pin 5),
lo
gives a lower demodulated amplitude and reduces the
lo
lo
and C
inductor and C
Ω
minimum.
RMS
lo
to reduce the Q factor of the tank
to prevent clipping by the internal
lo
capacitor. The tank circuit
Ω
, the load impedance
General description
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