All digital 625Mbps & 2.5Gbps deskew buffer design

Abstract

This paper describes an all digital 625Mbps and 2.5Gbps de-skew design for data recovery. It uses a confidence counter to serve as the loop filter that greatly reduces the circuit complexity and improves the jitter compression. The 625Mbps version has been implemented using TSMC 0.18um 1P6M CMOS technology. Measurement results show that the phase resolution is 100ps and the de-skew range is 1.6ns. The output jitter is 48ps and the power consumption is 3.8 mW. For the 2.5Gbps version, the simulation results show that the timing resolution is 26ps, the total de-skew range is 400ps, the output jitter is 26.5ps, and the power consumption is 16 mW.