Wide-range and low supply dependency MOSFET-based temperature sensor utilizing statistical properties of scaled MOSFETs

Abstract

We present a MOSFET-based temperature sensing method capable of high-accuracy temperature estimation across a wide temperature range while having a low supply voltage dependency. Existing MOSFET-based sensors, while capable of low-power operation, suffer from low sensing accuracy and a narrow sensing range. The proposed method utilizes per-MOSFET parameter variations seen in scaled CMOS processes. By measuring a statistical parameter of sub-threshold drain currents, we can extract a complimentary temperature value. To prove the feasibility of our method, we measure six chips fabricated with a commercial 65 nm process. The proposed method achieves a sensing accuracy of −0.54/ + 0.43 °C within a temperature range of −20 °C to 120 °C at a supply voltage of 1.2 V. In addition, the proposed method has a worst-case supply dependency of only 1.8 °C V−1 at 20 °C.