A Digital Power Amplifier With Built-In AM–PM Compensation and a Single-Transformer Output Network

This paper presents a digital power amplifier (DPA) with built-in AM-PM compensation technique and compact single-transformer footprint. The distortion behavior of the current mode/voltage mode PAs are detailed an for both modes is introduced. proposed design utilizes one current-mode as main path PA class-G voltage auxiliary PA, combined through single transformer It provides enhanced linearity adaptive biasing hybrid current/voltage Doherty-based combing. As proof-of-concept, 1.2-2.4 GHz wideband DPA implemented in Globalfoundries 45nm CMOS SOI process. measurements show 37.6% peak drain efficiency (DE) at 1.4GHz, 21.8dBm saturated output (Psat) 1.2×/1.4× PBO enhancement, compared to ideal class-B 3dB/6dB 1.2GHz. supports 20MSym/s 64-QAM modulation 14.8dBm average 22.8% DE while maintaining error vector magnitude (EVM) lower than -23dB without any phase pre-distortion. To best our knowledge, this first demonstration current-voltage Doherty combining on footprint over broad bandwidth (BW).