A 5-Gb/s Digital Clock and Data Recovery Circuit With Reduced DCO Supply Noise Sensitivity Utilizing Coupling Network

Abstract

A digital clock and data recovery (CDR) is presented, which employs a low supply sensitivity scheme for a digitally controlled oscillator (DCO). A coupling network comprising capacitors, resistors, and coupling buffers enhances the supply variation immunity of the DCO and mitigates the jitter performance degradation. A supply variation-dependent bias generator produces the corresponding bias voltage to alleviate the supply variation with minimal area and power penalty. The proposed scheme improves 29.3 ps of peak-to-peak jitter and 11.5 dB of spur level, at 6 and 5 MHz 50 mV(pp) sinusoidal supply noise tone, respectively. Fabricated in a 65-nm CMOS process, the proposed CDR operates at 5-Gb/s data rate with BER < 10(-12) for PRBS 31 and consumes 15.4 mW. The CDR occupies an active die area of 0.075 mm(2).