Panasonic KX-TG5771BXS Service Manual page 29

4.9.2. 2.4 GHz Mod/Demod Circuit
IC701 incorporates all of the modulation and demodulation functions. TX Digital data (TX_DATA) from DSP is supplied to pin 27 of
IC701, and then 2.4 GHz TX modulated signal is output from pin 1. This TX signal goes into the 5.8 GHz Converter circuit. 2.4 GHz
RX signal from 5.8 GHz Converter circuit is passed through matching circuit and supplied to pin 4 of IC701, then demodulated
signal (RX_DATA) comes out from pin 16. At the same time, RSSI (Received Signal Strength Indicator) outputs from the pin 14.
Reference clock (13.824 MHz) from DSP block is supplied to pin 11 of IC701. VCC_2.4 G supplies 2.5 V regulated voltage.
Note:
The exposed GND_PLATE on the bottom of the IC701 supplies the circuit ground(s) for the entire chip. It is very important that
a good solder connection is made between this GND_PLATE and the ground plane of the PCB underlying the IC701.
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KX-TG5771BXS/KX-TGA570BXS