A 20dBm outphasing class E PA with high efficiency at power back-off in 65nm CMOS technology

Abstract

This paper presents an outphasing class E PA (OEPA) in a 65nm CMOS technology, using a pcb transmission-line based power combiner. The OEPA can provide +20dBm output power from VDD=1.25V at 1.4GHz with 61% drain efficiency (DE) and 58% power added efficiency (PAE). We introduced a technique to rotate and shift power and efficiency contours of the two branch PAs that enables more than 44dB output power dynamic range, reduces switch voltage stresses compared to conventional OEPAs and enables 41% DE and 24% PAE at 12.5dB back-off.