20-Gb/s 3.6-VPP-swing source-series-terminated driver with 2-Tap FFE in 65-nm CMOS

A 20 Gb/s source-series-terminated (SST) driver that provides large output swing for optical modulator is presented. This work incorporates a stacked SST driver to enlarge output swing up to 3.6 V_{PP, Diff}. For high-speed operation over 20 Gb/s, the stacked SST driver is implemented with only thin-oxide devices. In addition, a 2-tap feed-forward equalizer (FFE) is employed to offer pre-emphasis that can compensate non-ideal effects in the optical modulator or interconnection. The prototype is fabricated in 65-nm CMOS process. Electrical measurement results show that the proposed driver achieves 3.6 V_{PP, Diff} output swing at 20 Gb/s. The power consumption of the prototype is 477 mW with 1.2 V and 2.4 V dual supplies. The prototype occupies 0.24-mm² active area.