A 5 Gb/s low power current-mode transmitter with pre-emphasis for serial links

Abstract

A multi-standard compatible transmitter with pre-emphasis for high speed serial links is presented. Based on the comparison between voltage mode (VM) and current mode (CM) output driver architectures, a low power CM output driver with reverse scaling and bias current filtering technique is proposed. A 2-tap pre-emphasis filter is used to reduce the intersymbol interference caused by the low-pass channel, and a high speed, low power combined serializer is implemented to convert 10 bit parallel data into a serial data stream. The whole transmitter is fabricated in 65 nm 1.2 V/2.5 V CMOS technology. It provides an eye height greater than 800 mV for data rates of both 2.5 Gb/s and 5 Gb/s. The output root mean square jitter of the transmitter at 5 Gb/s is only 9.94 ps without pre-emphasis. The transmitter consumes 41.2 mA at 5 Gb/s and occupies only 240 × 140 μm2.