A highly linear CMOS temperature sensor

Abstract

In this work, we proposed a linear CMOS temperature-to-current converter as a temperature sensor, which especially benefit on enhancing the accuracy of thermal monitoring. The proposed design achieves highly linear relationship between temperature and current by annulling the most critical nonlinear square terms of it. Through utilizing a compensation scheme among two current sources driven in saturation region with different bias voltages, the nonlinear effect originated from the temperature dependence of both mobility degradation and threshold voltage drift is cancelled. The experiment results demonstrate competitive performance. The maximum temperature error and average power consumption of temperature sensor are merely ±0.022°C and 137.6µW respectively while the die area is about 27.1µm*18.3µm under the implementation of TSMC 0.35µm CMOS process with 3.3V power supply.