A 5.5-GHz multi-mode power amplifier with reconfigurable output matching network

Abstract

A 5.5-GHz multi-mode PA with a reconfigurable output matching network which enables near-optimal impedances for size-scaling MOS transistors is proposed. The required load adaption is realized by using two transformers along with stage-bypassing technique for impedance coarse tuning and a switched capacitor for impedance fine tuning. Using a 90-nm CMOS process, the proposed PA demonstrates a PAE enhancement of 2.2×, 3.0×, and 5.0× respectively at 6-dB, 9-dB, and 15-dB transmit power back-off.