An integrated 60GHz 5Gb/s QPSK transmitter with on-chip T/R switch and fully-differential PLL frequency synthesizer in 65nm CMOS

Abstract

An integrated 60GHz 5Gb/s QPSK transmitter with on-chip T/R switch and fully-differential PLL frequency synthesizer in 65nm CMOS is presented. Direct QPSK modulation is implemented during the first up-conversion, followed by the final up-conversion mixer and power amplifier (PA) as well as on-chip T/R switch. Distributed amplifier technique is utilized to extend the bandwidth of PA. Along with other bandwidth extension techniques, in-band gain variation in signal link is minimized to improve the error vector magnitude (EVM). To reject common-mode noise and improve phase noise performance, a 40GHz fully-differential PLL frequency synthesizer is implemented to provide LO signals and various clocks. The measured output power is 6.4dBm at 60GHz, with 1.2dB gain variation over >6GHz bandwidth. On-chip 27-1 PRBS generators are used to measure the transmitter performance, and the measured EVM is -21.9dB with 5Gb/s QPSK modulation. The transmitter and the PLL & LO distribution network consume 73mW and 62mW, respectively.