A 2.5-Gb/s clock and data recovery circuit with ΔΣ-modulated fractional frequency compensation

Abstract

A 2.5-Gb/s clock and data recovery (CDR) circuit is presented, which employs an oversampling technique to recovery the data and an offset-frequency calibrated technique to compensate the frequency error between input rate and output clock. The offset-frequency calibrated technique is based on the ΔΣ modulated phase-lock-loop topology that can calibration frequency offset ±200MHz. Simulated by 0.18-μm CMOS technology, the retimed clock and the recovery data have the jitter of 10.1 ps and 11.7 ps, respectively (peak-to-peak). It consumes power dissipation of 152 mW under a 1.8-V supply.I.