6.7 A 112Gb/s PAM-4 Voltage-Mode Transmitter with 4-Tap Two-Step FFE and Automatic Phase Alignment Techniques in 40nm CMOS

Abstract

The continuous development of wireline communication encourages transmitters to operate at higher speeds. The applications of 400GbE also push the transmitter to be designed at 112Gb/s for a single lane [1–2]. However, the use of advanced processes $(\lt16$ nm) hardly reduces the costs. This paper presents a 112Gb/s PAM-4 voltage-mode transmitter fabricated in 40nm CMOS by using the proposed two-step FFE and the automatic phase alignment techniques, improving the output bandwidth as well as the power dissipation. It delivers high-quality eye diagrams under 5.5dB loss at 28GHz with 3.89pJ/b efficiency.