A 0.5 V, 112 nW CMOS Temperature Sensor for RFID Food Monitoring Application

Abstract

In this paper, a low-power on-chip temperature sensor, which is appropriate for food monitoring in ultra-high frequency radio frequency identification (UHF RFID) passive tag is proposed. For designing sensor core, MOSFET is used as a temperature sensing element and for decreasing the power consumption, and transistors are biased in sub-threshold region. In this sensor for converting the temperature to the digital code, the delay generator and the 10-bit binary counter are utilized. In the design of binary counter, the low-power and high-speed T Flip Flop (T-FF) is used in the digital part of sensor, based on gate diffusion input (GDI) technique. The proposed temperature sensor has 38 nW power consumption, 0.5 V supply voltage and −0.1/0.3 °C error due to the Monte Carlo analysis in the temperature range of −10 to 20 °C. The simulation is done with Cadence software in 180 nm CMOS TSMC Technology, while the chip area is 0.0125 mm2.