Design of half-rate clock and data recovery circuits for optical communication systems

This paper describes the design of two half-rate clock and data recovery circuits for optical receivers. Targeting the data rate of 10-Gb/s, the first implementation incorporates a ring oscillator and a linear phase detector whereas the second implementation uses a multiphase LC oscillator and a bang-bang phase/frequency detector. Fabricated in 0.18-μm CMOS technology, the power consumption of each of the circuits is less than 100 mW. The rms jitter of the output clock for the two prototypes is 1 ps and 0.8 ps, respectively, while the latter achieves a capture range of more than 14%.