A 2548-<i>μm<sup>2</sup></i> DTMOST-based temperature sensor with 3<i>σ</i> inaccuracy of ±0.89°C from -40°C to 125°C in 55 nm CMOS

This letter presents a 2548-µm2 CMOS temperature sensor. It uses a self-regulated capacitively-biased dynamic threshold MOS (DTMOST) and a simple CTAT reference source as front-end to generate a temperature-dependent clock signal, which is then fed into a counter-based frequency-to-digital converter (FDC), yielding a digital readout. Implemented in a standard 55 nm CMOS process, the sensor has 942.5 µm2 front-end area, achieves an inaccuracy of ±0.89 ℃ (3σ) from -40 ℃ to 125 ℃ after one-point calibration in batch. It consumes 6.15 µW and achieves a resolution of 14.5 mK and a resolution figure of merit (FoM) of 2.1 pJ･K2.