A 6-Gb/s PAM-3 transceiver with background time-varying offset sensing and compensation

Abstract

Time-varying offset such as transistor aging increases mismatches of differential pairs at pulse amplitude modulation (PAM)-3 transceivers, exacerbating signal integrity. To tackle this issue, this letter proposes a time-varying offset sensing and compensation technique for a PAM-3 transceiver. The proposed compensation algorithm continuously monitors the offset by detecting faulty sensing output patterns and generates optimal reference voltage for the single-to-differential amplifier and decision feedback equalizer to cancel out the offset. The proposed 6-Gb/s PAM-3 transceiver was fabricated in 65-nm CMOS technology. The proposed offset compensation technique improves the worst-case eye-openings by 38% compared to the baseline design.