A Reference-Less Clock and Data Recovery Circuit Using Phase-Rotating Phase-Locked Loop Guanghua Shu, Student Member , IEEE, Saurabh Saxena, Woo-Seok Choi, Mrunma y Talegaonkar, Rajesh Inti

Abstract

A reference-less half-rate digital clock and data recovery (CDR) circuit employing a phase-rotating phase-locked loop (PRPLL) as phase interpolator is presented. By implementing the proportional control in phase domain within the PRPLL, the proposed CDR decouples jitter transfer (JTRAN) bandwidth from jitter tolerance (JTOL) corne r frequency, eliminates jitter peaking, and removes JTRAN de pendence on bang-bang phase detector gain. Fabricated in a 90 nm CMOS process, the prototype CDR achieves error-free operation (BER < 10 )w i t hP R B S data sequences ranging from PR B S 7t oP R B S 3 1 .A t5G b / s ,i tc o n - sumes 13.1 mW power and achieves a recovered clock long-term jitter of 5.0 ps /44.0 ps when operating with PRBS31 input data. The measured JTRAN bandwidth is 2 MHz and JTOL corner frequency is 16 MHz. The CDR is tolerant to 110 mV of sinusoidal noise on the DCO supply voltage at the worst case noise frequency of 7 MHz. At 2.5 GHz, the PRPLL consumes 2.9 mW and achieves 134 dBc/Hz phase noise at 1 MHz frequency offset. The differential and integral non-linearity of its digital-to-phase transfer characteristic are within 0.2 LSB and 0.4 LSB, respectively.