Wide-range tracking technique for process-variation-robust clock and data recovery applications

A wide-range tracking technique for clock and data recovery（CDR） circuit is presented. Compared to the traditional technique, a digital CDR controller with calibration is adopted to extend the tracking range. Because of the use of digital circuits in the design, CDR is not sensitive to process and power supply variations. To verify the technique, the whole CDR circuit is implemented using 65-nm CMOS technology. Measurements show that the tracking range of CDR is greater than ±6×10-3 at 5 Gb/s. The receiver has good jitter tolerance performance and achieves a bit error rate of 〈10–12. The re-timed and re-multiplexed serial data has a root-mean-square jitter of 6.7 ps.