Motorola ASTRO XTS 5000 I Basic Service Manual page 34

Basic Theory of Operation
10
analog/digital converter (ADC), which is used to monitor volume
setting and battery voltage. This IC is programmed by the dual-core
processor.
The audio power amplifier (PA) drives the speakers with the received
audio from the analog output of the CODEC from the audio and
power supply IC. The audio PA is sourced from the battery (nominal
value of 7.5 volts). It is programmed by the dual-core processor.