The Xicor X9470 RF PA Bias Controller contains all of the necessary analog components to sense the PA drain current through an external sense resistor and automatically control the gate bias voltage of an LDMOS PA. The external sense resistor voltage is amplified by an instrumentation amplifier and the output of the amplifier along with an external reference voltage is fed to the inputs of a comparator. The comparator output indicates which direction the LDMOS gate bias voltage will move in the next calibration cycle. System calibration is accomplished by enabling the X9470 and providing a clock to the SCL pin. The LDMOS drain current can be maintained constant over temperature and aging changes by periodic calibration. The VOUT pin can be used to monitor the average power by tracking the drain current. Up to eight X9470 or additional Xicor Digital Potentiometers can be controlled via a two-wire serial bus.