A 47nW, 0.7-3.6V wide Supply Range, Resistor Based Temperature Sensor for IoT Applications

A sub 1-V, ultra low power temperature sensor has been implemented in TSMC 180 nm. The architecture is digital friendly since it creates a pulse width modulated wave instead of voltage. It uses proportional to absolute temperature(PTAT) characteristics of resistance to generate PTAT delay. Temperature to delay conversion depends only on passive elements, thereby making the circuit insensitive to supply variations. Line sensitivity of 0.23 °C/V is achieved for a wide supply range of 0.7-3.6V. A non linearity error of less than 0.8 °C is measured for -55 to 125 °C using linear fit curve. This occupies an area of 0.82 mm ₂ and consumes a power of 47 nW at 0.8 V supply.