A precision 140MHz relaxation oscillator in 40nm CMOS with 28ppm/°C frequency stability for automotive SoC applications

Abstract

The need for high-frequency, low-power, wide temperature range, precision on-chip reference clock generation makes relaxation oscillator topology an attractive solution for various automotive applications. This paper presents for the first time a 140MHz relaxation oscillator with robust-against-process-variation temperature compensation scheme. The high-frequency relaxation oscillator achieves 28 ppm/°C frequency stability over the automotive temperature range from −40 to 175°C. The circuit is fabricated in 40nm CMOS technology, occupies 0.009 mm2 and consumes 294µW from 1.2V supply.