A PLL/DLL based CDR with ΔΣ frequency tracking and low algorithmic jitter generation

Abstract

A delay- and phase-locked loop (D/PLL) based clock and data recovery (CDR) system enables an independent bandwidth control for jitter transfer and jitter tolerance but requires careful loop design with PVT-sensitive analog building blocks. In this work, an all-digital DLL and a digitally-controlled type-I boosted-gain fractional-N PLL followed by an injection-locked oscillator (ILO) are designed to realize a semidigital CDR system with enhanced frequency tracking capability and low algorithm jitter generation. The proposed CDR designed in 90nm CMOS consumes 26.4mW from a 1.2V supply and occupies the active area of 1.17mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> .