A 56-Gb/s 0.11-pJ/bit/dB Energy-Efficient PAM-4 Transmitter Using Push-Pull Current-Mode Driver and DDJ-Suppressed Multiplexer

Abstract

This brief presents a power-efficient PAM-4 transmitter. The proposed hybrid voltage-mode current-mode (VM-CM) driver with push-pull current-mode equalization reduces the power consumption. The date-dependent jitter (DDJ) suppressed C²MOS MUX is devised to reduce the output jitter and power of prior widely used C²MOS MUX. The phase aligner is utilized to provide sufficient time margin for the high-speed 4-1 MUX, thus no power-hungry high-speed latches along with its clock buffer are required for retiming. Fabricated in 40-nm CMOS, our prototype can operate at 56 Gb/s data rate with 0.7 pJ/bit energy efficiency and 6.1 dB channel loss at Nyquist frequency of 14 GHz, namely achieving a figure-of-merit (FOM) of 0.11 pJ/bit/dB.