A Digitally Controlled Oscillator for Low Jitter All Digital Phase Locked Loops

This paper presents a digitally controlled oscillator (DCO) for high speed ADPLLs. The proposed DCO circuit has control codes of thermometer type, which can reduce jitters. Performance of the DCO is verified through a novel ADPLL. The ADPLL chip with the DCO was fabricated using a 0.18mum CMOS technology. The ADPLL has operation range between 520MHz and 1.5GHz and has 76ps peak-to-peak jitter at 668MHz