A 32 GHz 20 dBm-PSAT transformer-based Doherty power amplifier for multi-Gb/s 5G applications in 28 nm bulk CMOS

This paper presents a 32 GHz transformer-based Doherty power amplifier (PA) in a 28 nm bulk CMOS process. There are two techniques proposed: linearization by means of AM-PM and AM-AM compensation of the class AB and the class C amplifiers; and parallel-series-parallel power power combiner, wherein a current-mode parallel combiner complements the Doherty's voltage-mode series combiner to boost the output power. A saturated output power (P
_SAT
) of 19.8 dBm and an OP1dB of 16 dBm are accomplished from 1V supply while supporting 15 Gb/s 64-QAM amplification at 11.7 dBm average output power. The chip achieves 21% PAE at P
_SAT
and occupies 0.59 mm
²
active area.