A Millimeter-Wave ADPLL With Reference Oversampling and Third-Harmonic Extraction Featuring High FoM_jitter-N

This letter proposes a mm-wave fractional-N reference-oversampling (ROS) ADPLL for 5G applications utilizing relatively low but standard reference frequency. The 4× ROS phase detector (PD) increases the detection rate in power-efficient manner order to reduce in-band noise contributed from PD. improves overall FoM and locking speed. A class-F3 oscillator generates both 10 GHz its third harmonic. former is fed feedback divider, while latter extracted generate 30 output. fractional distortions are compensated digital with assistance of DACs. proposed ROS-ADPLL implemented 28-nm CMOS. Using 50 MHz frequency, it achieves 237 fs rms jitter consuming only 11.9 mW, achieving best-in-class FoMjitter-N –269.3 dB.