A 1-V 15μW High-Accuracy Temperature Switch

A CMOS temperature switch with uncalibrated high temperature accuracy is presented. The circuit is based on the classical CMOS bandgap reference structure, using parasitic PNPs and a PTAT multiplier. The circuit was designed in a standard digital 0.18 μm CMOS process. The temperature switch has a in-designed hysteresis of 1.2 °C around a threshold value of 128 °C. At the switchingthreshold all matched transistors have also matched operating conditions, yielding a temperature threshold that is highly independent of transistor output resistance and supply voltage. With a chip area of only 0.03 mm, the on-wafer 3σ spread of the threshold temperature is 1.1 °C. Power consumption is only 15 μA at 1 Volt supply.