A 20-Gb/s Transmitter With Adaptive Preemphasis in 65-nm CMOS Technology

A 20-Gb/s transmitter with two-tap adaptive preemphasis is presented. For the channels with different lengths, the tap coefficients are adjusted by detecting the propagation time through a channel. This adaptive transmitter is fabricated in 65-nm CMOS technology. The maximum power consumption from a 1.2-V supply is 58.8 mW, and the chip area occupies 1.05 × 0.85 mm². For a 2-m coaxial copper cable with a 12.78-dB loss, the measured root mean square and peak-to-peak jitter of the recovered data are 2.56 and 18.67 ps, respectively, for a 20-Gb/s pseudorandom binary sequence of 2³¹-1. The measured bit error rate is less than 10^-12.