A 2.9 MHz low power RC relaxation oscillator with delay equivalent electric charges storage and fully covered trimming strategy

Abstract

A fully-integrated 2.9 MHz RC relaxation oscillator is presented in this paper. In order to eliminate performance degradation caused by propagation delay at low power, the delay equivalent electric charges technique based on comparator offset cancellation structure is utilized. The oscillator is designed in 180 nm CMOS process and 1-point trimmed to operate within 0.2% precision by a specific mathematical model. With core area of 0.115mm2, the oscillator achieves a frequency stability of 45 ppm/°C in range from −40∼+125 °C and demonstrates an energy efficiency of 2.49 μW/MHz.