A 2.5-Gb/s fully-integrated, low-power clock and recovery circuit in 0.18-μm CMOS

Abstract

Based on the devised system-level design methodology, a 2.5-Gb/s monolithic bang-bang phase-locked clock and data recovery (CDR) circuit has been designed and fabricated in SMIC's 0.18-μm CMOS technology. The Pottbäcker phase frequency detector and a differential 4-stage inductorless ring VCO are adopted, where an additional current source is added to the VCO cell to improve the linearity of the VCO characteristic. The CDR has an active area of 340 × 440 μm2, and consumes apower of only about 60 mW from a 1.8 V supply voltage, with an input sensitivity of less than 25 mV, and an output single-ended swing of more than 300 mV It has a pull-in range of 800 MHz, and a phase noise of −111.54 dBc/Hz at 10 kHz offset. The CDR works reliably at any input data rate between 1.8 Gb/s and 2.6 Gb/s without any need for reference clock, off-chip tuning, or external components.