Accuracy analysis of a new reference-free digital temperature sensor in CMOS

A CMOS digital temperature measurement technique is reported, which doesn't require an explicit reference voltage during temperature to digital conversion. Instead, one of the inputs from the sensor core serves as the reference. After eliminating the need to use an external reference, we observe at least twofold increase in temperature estimation accuracy compared to the reference based traditional approach. Designed in 65nm CMOS, the digital sensor consume a total power of 220μν and an area of 0.25mm², and achieves a ±3σ accuracy of 1°C after curvature correction and room temperature trim.