A +32 dBm 1.85 GHz Class-D Outphasing RF PA in 130nm CMOS for WCDMA/LTE

Amplifier (PA) which can operate at a 5.5 V supply and deliver +32 dBm at 1.85 GHz in a standard 130nm CMOS technology. The PA utilizes four on-chip transformers to combine the outputs of eight Class-D stages. The Class-D stages utilize a cascode configuration, driven by an AC-coupled low-voltage driver, to allow a 5.5 V supply in the 1.2/2.5 V 130nm process without exces-sive device voltage stress. Spectral and modulation requirements were met when a WCDMA and an LTE signal (20 MHz, 16-QAM) were applied to the outphasing PA. At +28.0 dBm channel power for the WCDMA signal, the measured ACLR at 5 MHz and 10 MHz offset were-38.7 dBc and-47.0 dBc, respectively. At +24.9 dBm channel power for the LTE signal, the measured ACLR at 20 MHz offset was-34.9 dBc. To the authors ’ best knowledge, the PA presented in this work has a 3.9 dB higher output power compared to published CMOS Class-D RF PAs. Index Terms—outphasing, CMOS, power amplifier. I