A fully integrated 0.18 /spl mu/m 1P6M CMOS power amplifier using internal frequency doubling is presented. Two chips were measured, one stand-alone PA and one PA with a VCO on the same chip. Since the PA and VCO operate at different frequencies, this configuration is suitable for direct-upconversion or low-IF upconversion since oscillator pulling is reduced. The maximum output power is 15 dBm, and the maximum drain efficiency is 10.7% at an output operating frequency of 2.4 GHz.