A 2-40 Gb/s PAM4/NRZ dual-mode wireline transmitter with 4:1 MUX in 65-nm CMOS http://researchonline.ljmu.ac.uk/8698/ Article LJMU has developed LJMU Research Online for users to access the research output of the University more effectively.Abstract-This paper presents a 2-40 Gb/s dual-mode wireline transmitter supporting the four-level pulse amplitude modulation (PAM4) and non-return-tozero (NRZ) modulation with a multiplexer (MUX)based two-tap feed-forward equalizer (FFE). An edgeacceleration technique is proposed for the 4:1 MUX to increase the bandwidth. By utilizing a dedicated cascode current source, the output swing can achieve 900 mV with a level deviation of only 0.12% for PAM4. Fabricated in a 65-nm CMOS process, the transmitter consumes 117 mW and 89 mW at 40 Gb/s in PAM4 and NRZ at 1.2 V supply.
Index Terms-Four-level pulse amplitude modulation (PAM4), non-return-to-zero (NRZ), edge-acceleration technique, linearity optimization, dual-mode wireline transmitter