A 8 Phases 192 MHz Crystal-Less Clock Generator with PVT Calibration

Abstract

A multi-phase crystal-less clock generator (MPCLCG) with a process-voltage-temperature (PVT) calibration circuit is proposed. It operates at 192 MHz with 8 phases outputs, and is implemented as a 0.18pm CMOS process for digital power management systems. A temperature calibrated circuit is proposed to align operational frequency under process and supply voltage variations. It occupies an area of 65 mu m x 75 mu m and consumes 1.1 mW with the power supply of 1.8 V. Temperature coefficient (TC) is 69.5 ppm/degrees C from 0 to 100 degrees C, and 2-point calibration is applied to calibrate PVT variation. The measured period jitter is a 4.58-ps RMS jitter and a 34.55-ps peak-to-peak jitter (P2P jitter) at 192 MHz within 12.67k-hits. At 192 MHz, it shows a 1-MHz-offset phase noise of -102 dBc/Hz. Phase to phase errors and duty cycle errors are less than 5.5% and 4.3%, respectively.