A 32.75-Gb/s Voltage-Mode Transmitter With Three-Tap FFE in 16-nm CMOS

This paper describes a 32.75-Gb/s voltage-mode transmitter (TX) with three-tap feed forward equalization that is fabricated in a 16-nm FinFET CMOS technology. The TX uses a dual regulator architecture to allow independent control of output swing, output common-mode, and equalization. A hybrid impedance control scheme is presented where the total number of driver slices is used for coarse impedance control, and analog loop-based voltage control is used for fine impedance control of the TX. A finite-impulse response compensation circuit to compensate for the data dependent current due to equalization is also presented. The TX consumes 120.8 mW with 0.9- and 1.2-V supplies, provides 0.25–0.9 V pp output swing, and achieves total jitter of 6.49 ps–pp and random jitter of 220 fs–rms at 32.75 Gb/s with bit error rate of 1e-12.