A multiphase switched capacitor power amplifier in 130nm CMOS

Abstract

This paper presents a multiphase switched-capacitor power amplifier (MP-SCPA). Cartesian combining architectures suffer reduced output power and efficiency owing to combination of out-of-phase signals. The multiphase architecture reduces the phase difference between the basis vectors that are combined, increasing the output power and efficiency compared to the Cartesian combiners. 16 equally spaced phases are produced by a phase generator with each phase's relative amplitude weighted on the bottom plate of a capacitor array and combined on a common top plate, resulting in linear amplification. The MP-SCPA delivers a peak output power and PAE of 26 dBm and 24.9%, respectively. When amplifying an LTE signal the average output power and PAE are 20.9 dBm and 15.2%, respectively while achieving <;-30 dBc ACLR and 3.5 %-rms EVM.