60GHz Transmitter Front-End in 40nm LP-CMOS with Improved Back-Off Efficiency

60GHz Transmitter Front-End in 40nm LP-CMOS with Improved Back-Off Efficiency ■

Khaled Khalaf, Khaled Khalaf, Khaled Khalaf, Vojkan Vidojkovic, Vojkan Vidojkovic, Vojkan Vidojkovic, Kristof Vaesen, Kristof Vaesen, Kristof Vaesen, Bertrand Parvais, Bertrand Parvais, Bertrand Parvais, John Long, John Long, John Long, Piet Wambacq, Piet Wambacq, Piet Wambacq

Abstract ■

A three-stage, transformer-coupled class-AB power amplifier (PA) and a super source-follower-based I-Q upconversion mixer are implemented in 40nm LP-CMOS technology. The transmitter (Tx) front-end is designed for multi-Gbps QPSK/QAM-16 signal transmission at 60GHz with improved back-off efficiency. It achieves 5.7\% power-added efficiency (PAE) at 5dB back-off with a total power consumption of only 90mW. Power gain and output 1dB compression point (P-1dB) are 22dB and 10.2dBm, respectively. A second Tx front-end, based on a class-A PA and Gilbert-cell upconversion mixer, is designed as a benchmark for comparison. With a similar value of P-1dB, PAE of the class-AB prototype at 5dB back-off is three times higher and the total power consumption is 100mW lower than the benchmark Tx.