A 105-nW CMOS thermal sensor for power-aware applications

We propose an ultra-low power thermal sensor consisting of a nano-ampere CMOS current source circuit and a single bipolar transistor. Since the stability of current source circuits is the most important issue for our thermal sensor, we developed a circuit with an improved process and temperature stability. Our simulations and the measurements we conducted on the proposed thermal sensor demonstrated that it can be robustly operated in a wide temperature range. The power dissipation of the circuit was 105 nW for a 3-V power supply. The accuracy was within ±1°C in a wide temperature range of -20 to 120°C.