A novel and useful apparatus for and method of predistortion calibration and built-in self testing (BIST) of a nonlinear digitally-controlled radio frequency (RF) power amplifier (DPA) using subharmonic mixing. The RF power amplifier output is temporarily coupled into the frequency reference (FREF) input and the phase error samples generated in the phase locked loop (PLL) are then observed and analyzed. The digital predistortion and BIST mechanisms process the phase error samples to calibrate and test the DPA in the transmitter of the Digital RF Processor (DRP). The invention enables the characterization of nonlinearities, the configuration of internal predistortion, as well as the testing of the transmitter's analog/RF circuitry, thereby eliminating commonly employed RF performance testing using high-cost test equipment and associated extended test times.