Thermal diffusivity sensors for wide-range temperature sensing

This work presents a CMOS temperature sensor based on thermal diffusivity sensing. This sensor is insensitive to leakage currents, and so can reliably operate up to and beyond 150degC. Also, thermal diffusivity sensors have low intrinsic spread, which means that in many applications, they do not require trimming. A thermal diffusivity sensor and its interface circuit were realized in 0.7 mum CMOS technology. The untrimmed device-to-device spread corresponds to a temperature error of plusmn0.7degC (3sigma) from -70degC to 160degC. This operating range is a significant improvement on the state-of-the-art.