Process, voltage and temperature compensation in a 1-MHz 130nm CMOS monolithic clock oscillator with 2.3% accuracy

Abstract

This paper presents an on-chip process, voltage and temperature (PVT) compensation technique for a 1-MHz monolithic clock oscillator in a CMOS process. The oscillator is based on carrier mobility and frequency-to-voltage converter (FVC), which is based on charge pump circuit. An adaptive charge current maintains a constant frequency without trimming. Furthermore, a reference voltage with a second-order temperature coefficient further compensates the variation of frequency with temperature. It improves the accuracy of existing carrier-mobility-based oscillator, from 4.5% to 2.3%. The circuit was designed in a 130 nm CMOS 3.3 V device process. The results show that the output frequency is within 2.3% variation in the worst case. The variations of frequency with process, temperature (−40 to 125°C) and power supply are within 1.8%, 0.8% and 0.2%/V, respectively. It achieves a CMOS monolithic clock oscillator insensitive to PVT.