We present a mmWave three-way Doherty output network and its silicon implementation at 38 GHz for 5G NR OFDM. The proposed network synthesis methodology can realize close-to-ideal dual-peaking Doherty active load mod ulation, reduce the impedance transformation ratio at back-off, and directly absorb the device parasitic capacitance. Its design procedure and trade-offs are discussed in detail. A 38-GHz PA

prototype is implemented in the GlobalFoundries 45-nm CMOS SOI process, achieving 13.7% / 11.0% PAE at the 9.5-dB / 11.5-dB back-off, which are among the highest compared to recently reported silicon PAs operating at 30 GHz and above. Tested under 1-CC and 2-CC 5G NR FR2 64-QAM OFDM signals in the Band n260, the PA demonstrates state-of-the-art average output power(11.3 dBm) and average efficiency (14.7%) with -25 dB EVM. The design robustness and reliability is further demonstrated through the testing of multiple samples and PA lifetime