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arXiv · 1905.00273

A fully-digital semi-rotational frequency detection algorithm for bang-bang CDRs

Soon-Won Kwon·Hanho Choi·Younho Jeon·Bongjin Kim·WooHyun Kwon·Homin Park·Kyeongha Kwon·Gain Kim·Hyeon-Min Bae
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Abstract

This work presents a new frequency acquisition method using semi-rotational frequency detection (SRFD) algorithm for a reference-less clock and data recovery (CDR) in a serial-link receiver. The proposed SRFD algorithm classifies the bang-bang phase detector(BBPD) outputs to estimate the current phase state, and detects the frequency mismatch between the input data and the sampling clock. The VCO-track path in a digital loop filter (DLF) enables online calibration of a drifted frequency of VCO caused by temperature or voltage variation after a frequency acquisition. The proposed algorithm can be implemented as a digitally-synthesized circuit, lowering design efforts for referenceless CDRs. A 10 Gbps transceiver IC with the proposed algorithm, fabricated in a 65nm CMOS process, demonstrates successful recovery of the input phase without any reference clock.

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Soon-Won Kwon, Hanho Choi, Younho Jeon, Bongjin Kim, WooHyun Kwon, Homin Park, Kyeongha Kwon, Gain Kim, Hyeon-Min Bae. 2019-05-01. A fully-digital semi-rotational frequency detection algorithm for bang-bang CDRs. https://arxiv.org/abs/1905.00273

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