A 2 MHz High Stability On-Chip Relaxation Oscillator with a 2.5-5.5-V Voltage Supply

This paper proposes a high stability on-chip RC relaxation oscillator. A voltage average feedback technique is employed to mitigate the impact of comparator delay and a reference circuit is used to achieve high stability frequency over a wide power supply voltage and temperature range. Considering manufacturing process variations, a digital trimming circuit is used to obtain better accuracy. Designed in a 180-CMOS process, the target frequency of the proposed oscillator is 2 MHz. The frequency deviation is 0.516% over a supply range of 2.5 to 5.5V and 0.321% for temperature across -40℃ to 125℃.