A High-Efficient CMOS RF Power Amplifier With Automatic Adaptive Bias Control

A 2.4-GHz Doherty power amplifier (PA) is developed in 0.18-$mu$m CMOS technology. An automatic adaptive bias control circuit is integrated with the auxiliary PA to improve the overall performance of the PA. Operated at 3V, theP₁ dBand associated power-added-efficiency (PAE) of the PA are 21dBm and 33%, respectively. At the output power 6-dB backoff fromP₁ dB, the PAE remains 21%. The limited PAE degradation at backoff power levels makes the PA suitable for the applications with high peak-to-average power ratio.