A 103 fs RMS Jitter Calibration-Free Gain-Boosting Quadrature Oversampling PLL Utilizing an Isolated Reference Sampling Phase Detector

Abstract

This letter presents a integer-N quadrature oversampling phase-locked loop (QOPLL) operating at 5.76-6.48 GHz with low RMS jitter. The QOPLL features a calibration-free gain-boosting quadrature oversampling mechanism. The proposed gain-boosting quadrature oversampling mechanism addresses the incompatibility issues in conventional oversampling mechanisms and gain-boosting techniques. It enhances in-band phase noise performance while eliminating the need for phase detector gain calibration. An isolated reference sampling phase detector (IRSPD) has been developed to ensure quadrature phase accuracy and improve phase detector gain. The QOPLL is fabricated in a 40-nm CMOS process. Measurement results demonstrate an RMS jitter of 103 fs, integrated from 10 kHz to 100 MHz. The reference spur is -71.26 dBc. The power consumption is 15 mW.