A power-combined switched-capacitor power amplifier in 90nm CMOS

A digitally-controlled switched-capacitor RF power amplifier (SCPA) is implemented with a transformer-based power-combiner in 90nm CMOS. The individual SCPA cores can be controlled to provide high average output power and linearity in an “all-switching” mode or increased dynamic range in a “sequential-switching” mode. The SCPA delivers a peak (average) output power of 27.0 (20.3) dBm with a peak (average) PAE of 26% (15.1%) for a 64 QAM OFDM modulated signal with a measured EVM of 3.8% in the 2.4 GHz band.