In the era of internet of things (IoT) and wireless communication, energy- and area-efficient wireless transceivers are critical for extended battery life and small form factor of many systems. On the other hand, innovations in analog circuits have been driven by rapidly evolving semiconductor technology in line with Moore’s law. A switched capacitor power amplification (SCPA) technique, based on RF switched capacitor digital-to-analog converter architecture, offers very high energy efficiency and superior linearity for wireless transmitters. The measured peak Pout and power-added-efficiency (PAE) of a prototype SCPA are 25.2 dBm and 45%, respectively. For 802.11g 64-QAM OFDM modulated signal, the average Pout and PAE are 17.7 dBm and 27%, respectively, and the measured EVM is 2.6% without any predistortion applied. Class-G technique can be applied to SCPA to further enhance the efficiency. With additional supply voltage and advanced switching scheme for multiple supply voltages, the measured peak Pout and PAE are 24.3 dBm and 43.5%, respectively, whereas the average Pout and PAE are 16.8 dBm and 33%, respectively, for 802.11g signals.
Sangmin Yoo received his Ph.D. degree in Electrical Engineering from the University of Washington, Seattle, in 2011. He also received B.S and M.S. degrees from Sogang University, Seoul, Korea, in 2000 and 2002, respectively. He is currently an Assistant Professor with the Department of Electrical and Computer Engineering at the Michigan State University. He was with Qualcomm from 2011 to 2016, where he was involved with the design of analog/mixed-signal/RF circuits and systems including wireless transceivers and RF power amplifiers. From 2002 to 2007, he was with Samsung, Korea, where he designed analog/mixed-signal circuits such as data converters and baseband analog circuits. He also held internship position with Intel, Hillsboro, from 2010 to 2011. His research interest includes RF and analog/mixed-signal circuits and systems including high-efficiency transmitter architecture, software defined radio, RF power amplifier, and data converter for various applications such as communication, biomedical, wearable or implantable device, energy harvesting, and automotive system.