In a mobile wireless telecommunication device, a bidirectional serial interface is used to transfer a digital representation of an analog value from a first chip associated with a power amplifier module to a second chip. In an exemplary embodiment, circuitry on the first chip receives this clock signal from the second chip during the address portion of a read operation and uses this clock signal to generate a conversion clock signal. An analog-to-digital converter (ADC) on the first chip operates in response to the conversion clock signal to convert an analog value to a digital output. Circuitry on the first chip then transfers the digital output of the ADC from the first chip to the second chip via the serial interface.