An area efficient temperature sensor with software calibration for mobile application

This paper presents an area-efficient temperature sensor with 1°C resolution based on a successive approximation algorithm. SoC requires several die temperature sensors to be integrated in a chip to manage the performance because die temperature directly affects leakage current level and performance of clock-based digital circuits. However, the size of temperatures sensor restricts the use of sensor in several places in a chip. The proposed area efficient temperature sensor uses only 0.13mm² in Samsung 45nm CMOS process to obtain 1°C resolution in the range from -15°C to 125°C. For accurate temperature sensing, SAR type algorithm and software-based 2-point calibration method are adopted. After the 2-point calibration, the temperature sensor achieves 1°C resolution with ±2°C accuracy and the power consumption is 360uW in 1.8V.