A Second-Order Temperature-Compensated On-Chip R-RC Oscillator Achieving 7.93ppm/°C and 3.3pJ/Hz in -40°C to 125°C Temperature Range

With the development of various miniaturized IoT applications, the need for on-chip time management has been growing rapidly. An on-chip RC oscillator is one of the promising candidates since it can be fully integrated with standard CMOS technology. Typically, an RC oscillator is implemented with a comparator that periodically resets a capacitor voltage at an interval defined by a fraction of the RC time constant to generate a stable output frequency. Therefore, the RC time constant needs to be invariant to the supply voltage and temperature changes. Also, the comparator must be high power, so that its temperature-dependent delay becomes negligible compared to the RC time constant.