A 2.25-mW/Gb/s 80-Gb/s-PAM4 linear driver with a single supply using stacked current-mode architecture in 65-nm CMOS

Abstract

This paper presents a low-power linear driver for a coherent optical transmitter. We propose a driver using stacked current-mode architecture to achieve low-power consumption with a single supply. The driver can drive from 25 to 50 Ω impedances with almost the same output waveforms by using a variable equalizer and adjusting the current of the post-amplifier. The proposed driver was fabricated in 65-nm CMOS technology and achieved the power efficiency of 3.6 mW/Gb/s with a differential output swing of 2.9 Vpp for a 50-Gb/s NRZ signal and 2.25 mW/Gb/s with a differential output swing of 2.0 Vpp for an 80-Gb/s PAM4 signal.