A 26 dBm 39 GHz Power Amplifier with 26.6% PAE for 5G Applications in 28nm bulk CMOS

Continued demand for 5G cellular connectivity in mobile handheld devices, where antenna real-estate is at a premium, necessitates high output power from individual transmitter elements. While more expensive heterogeneous and SOI CMOS process based power amplifiers (PAs) provide high P-out at good efficiencies, deep sub-mu m bulk CMOS still remains the technology of choice for cost and integration benefits. This paper presents a 5G mm-Wave PA at 39GHz that generates a saturated P-out of 26dBm with a peak power-added efficiency (PAE) of 26.6% and a saturated power gain of 28.6 dB. The output stage utilizes compact layout & triple-well transistors to enable efficient yet reliable device stacking and a compact, 4-way, low-loss, series-parallel power combiner further enhances P-out. High average power measurements have been demonstrated during single-carrier as well as 5GNR OFDM modulations at competitive efficiencies. Long term reliability measurements using aging acceleration techniques demonstrate the robustness of the implemented PA. This PA achieves one of the highest ITRS figure-of-merit among reported 5G mm-Wave works in CMOS and also the highest output power among deep sub-mu m (<90nm) 5G bulk CMOS PAs.