Self-Referenced 32-kHz Rotating Capacitor Relaxation Oscillator with Chopped Comparator Offset-Voltage Cancellation

This work presents a novel relaxation oscillator architecture using a rotating capacitor integrator and a chopped comparator. The oscillator is self-referenced, using the resistor instead of the current source, together with the reference voltage realized with the resistor divider connected to the supply voltage. The oscillator prototype is designed and manufactured in 180 nm technology, typically consumes 1.5 µA at 32 kHz, has a frequency variation of ±0.44% in the temperature range from −40 to 105°C and ±0.3% in the power supply range from 1.62 to 1.98 V. The oscillator has a start-up time of 15.4 µs and is operational in the low supply voltage range.