A 490-pW SAR Temperature Sensor With a Leakage-Based Bandgap-Vth Reference

This brief presents a temperature sensor that combines a leakage-based bandgap-Vth reference and an asynchronous SAR. The proposed sensor is implemented with 0.18 μm CMOS technology. By sampling leakage-based biases directly in the SAR ADC, the sensor consumes 490 pW at 20 °C with a conversion time of 200 ms and stably works with a 1-point calibration, showing a ±2.35 °C peak-to-peak inaccuracy from -10 to 100 °C. The proposed sensor can operate across a wide range of supply voltage of 1 V to 2.1 V, with a supply sensitivity of 1.073 °C/V.