Design Techniques for a 60-Gb/s 288-mW NRZ Transceiver With Adaptive Equalization and Baud-Rate Clock and Data Recovery in 65-nm CMOS Technology

Abstract

Design techniques for a complete 60-Gb/s non-return-to-zero transceiver with adaptive equalization as well as baud-rate clock and data recovery (CDR) are demonstrated. A complete equalization front end with per-path adaptation and per-sampler offset calibration enables 60-Gb/s operation over realistic channels. Current integration in the front end for energy-efficient equalization is combined with integration phase dithering to realize a robust baud-rate CDR. Correlation of the adaptive error sampler output with the phase dithering sequence indicates the direction of phase offset, and the resulting baud-rate CDR saves power and complexity compared to an oversampling CDR by not requiring additional clock phases/deserializers. The proposed 65-nm CMOS transceiver operates at 60 Gb/s with an eye opening of 30% UI and consumes 288 mW while equalizing 21 dB of loss at 30 GHz over a 0.7-m Twinax cable.