A 26GHz Balun-First Three-Way Doherty PA in 40nm CMOS with 20.7dBm Psat and 20dB Power Gain

This paper presents a 40nm CMOS mm-wave 3-way Doherty power amplifier (PA) suitable for 5G mm-wave transmitters. It features a bandwidth-enhanced technique using a compact single-supply balun-first 3-way Doherty combiner. The realized front-end with a core area of 0.77mm(2) delivers a peak power/gain of more than 20 dBm/16 dB and a drain efficiency (DE) of better than 15 %/22 %/33% at 9.5 dB/6 dB/0 dB power back-off across a 24-to-30GHz band. At 26 GHz, it achieves an EVM/ACLR of -23.5 dB/-29.5 dBc for an 800MHz 64-OFDM signal with 9.8dBm average output power and a 15% average DE.