A 10-gb/s CMOS clock and data recovery circuit with an analog phase interpolator

This paper presents a 10-Gb/s clock and data recovery (CDR) circuit for use in multichannel applications. The module aligns the phase of a plesiochronous system clock to the incoming data by use of phase interpolation. Thus, coupling between voltage-controlled oscillators (VCOs) in adjacent channels can be avoided. The controller for the phase interpolator is realized with analog circuitry to overcome the speed and phase resolution limitations of digital implementations. Fabricated in a 0.11-μm CMOS technology the module has a size of 0.25×1.4 mm². The power consumption is 220 mW from a supply voltage of 1.5 V. The CDR exceeds the SDH/SONET jitter tolerance specifications with a pseudo random bit sequence of length 2²³-1 and a bit-error rate threshold of 10^-12. The re-timed and demultiplexed data has an rms jitter of 3.2 ps at a data rate of 2.7 Gb/s.