A Quadrature Digital Power Amplifier with Hybrid Doherty and Impedance Boosting for Efficiency Enhancement in Complex Domain

In this paper, a quadrature digital PA with hybrid Doherty and impedance boosting (HDIB) is proposed using reconfigurable transformer for PBO efficiency enhancement in complex domain. With the HDIB tracking the optimum load-impedance for different PBOs in wideband, efficiency peaking at 3/6/9/12/15dB PBO is provided from 2.3-3.4GHz without any supply switching or PA short-switches. The fabricated 40-nm CMOS digital PA achieves 24.2dBm peak Pout with 38.5% drain efficiency (DE), and -32.3dB EVM for 10MHz 256QAM signals with average DE of 24.6%.