The ADC multiplexer provides selectable connections to the VCx inputs, TS1 inputs, internal temperature sensor, internal reference voltages, internal 1.8-V regulator, PACK input, and VSS ground reference input. In addition, the multiplexer can independently enable the TS1 input connection to the internal thermistor biasing circuitry, and also enables the user to short the multiplexer inputs for test and calibration purposes.