Low-power area-efficient wide-range robust CMOS temperature sensors

This paper proposes six different CMOS-based temperature sensor topologies by exploiting temperature dependence of MOSFET's threshold voltage VT, the carrier's mobility μ and the resistivity of n-well resistors. The proposed temperature sensors are designed for a wide temperature range of −100 °C to +120 °C and exhibit resolutions in the range of 0.04-0.448 °C along with readout sensitivities in the range of 0.37-1.83 mV/°C. For accuracy enhancement, automated single-point calibration is implemented for all topologies in conjunction with an off-chip reference temperature sensor. These calibrated temperature sensors exhibit measured inaccuracies between 0.2 °C and 1 °C for the proposed temperature range. These temperature sensors are designed in 0.25 μm TSMC 1P/5M process and are embedded in a 5 mm×5 mm imaging array readout IC to develop the thermal profile of the IC. The presented temperature sensors exhibit comparable performance metrics to state-of-the-art topologies in the literature with added advantage of a buffered output, which could be useful in case of a fast load drive and settling to implement faster control systems.