Nano Watt CMOS temperature sensor

Abstract

In this paper, an ultra-low power embedded full CMOS temperature sensor based on sub-threshold MOS operation is designed in a 0.18 μm CMOS technology. It focuses on temperature measurement using the difference between the gate-source voltages of transistors operated in sub-threshold region that is proportional to absolute temperature. By using the proposed scheme the wide range supply voltage of 0.6---2.5 V with inaccuracy of +0.55 °C/V and total power consumption of merely 7 nW at 120 °C is achieved. The performance of the sensor is highly linear and the predicted temperature error is ±2 °C in the range of 10---120 °C. The sensor occupies a small area of 67 × 31 μm2. Ultra-low power consumption of the sensor illustrates proper operation for low power applications such as battery powered portable devices, passive RFID tags and wireless sensor network applications.