All-digital SoC thermal sensor using on-chip high order temperature curvature correction

Accurate, compact thermal sensors are desirable in many applications, including on-chip temperature monitoring for processors with dynamic throttling and reliability management. Modern thermal sensors are limited in either area, robustness, or accuracy. This work sidesteps strong linearity requirements for reference and PTAT elements in the sensor by performing a higher-order fitting of more relaxed PTAT and CTAT elements using an embedded calculation compute engine. A compact 24 × 10μm sensing element (40nm CMOS) achieves inaccuracy of <1°C across 30 chips with 2-point calibration and a resolution of 0.02°C.