An on-chip smart temperature sensor based on band gap and SAR ADC

A new on-chip temperature structure is presented in this paper. This on-chip temperature is primarily composed of band gap and asynchronous SAR ADC. Band gap provides SAR ADC with negative temperature coefficient voltage V_BE and reference voltage which is independent of temperature. The resolution of asynchronous SAR ADC is 11 bits. The temperature sensor is implemented in CSMC 0.5um CMOS process with area of 2.04mm². Measurement results show that the accuracy of the temperature sensor is about 0.26°C by using high resolution ADC and linear calibration, SAR ADC ENOB of 9.69, band gap reference voltage of 1.28V, and total current of 1.3mA.