Panasonic KX-TG5621BXS, Service Manual

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15.3. 5.8GHz Converter Circuit
This block converts frequency of TX signal and RX signal.
IC801 includes TX-MIXER, RX-MIXER, PLL and VCO modules internally.
The VCO module is tuned by PLL synthesizer module, and generates 3.4GHz Local signal. Reference clock (13.824MHz) from
DSP block is supplied to pin7 of IC701.
2.4GHz TX signal from 2.4GHz Mod/Demod circuit is supplied to pin 17 of IC801, and internal TX-MIXER multiplies it by 3.4GHz
Local signal from internal VCO module, and up-converts into 5.8GHz TX signal. This 5.8GHz TX signal is output from pin 2, and
goes into the 5.8GHz PA circuit.
5.8GHz RX signal from 5.8GHz LNA circuit supplied to pin 5 of IC801, and internal RX-MIXER multiplies it by 3.4GHz Local signal
from internal VCO module, and down-converts into 2.4GHz RX signal. This 2.4GHz RX signal is output from pin 15, and goes into
the 2.4GHz Mod/Demod circuits.
Note:
The exposed GND-PLATE on the bottom of the IC801 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 IC801.
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KX-TG5621BXS / KX-TGA561BXS