Wide-range CTAT and PTAT sensors with second-order calibration for on-chip thermal monitoring

Abstract

This paper presents wide-range complementary to absolute temperature (CTAT) and proportional to absolute temperature (PTAT) sensors with second-order calibration for on-chip thermal monitoring. Particularly, a current mirror and an n-well resistor are used in these sensors to eliminate the second-order term of the temperature coefficient to linearize the transfer function between the output voltage and the temperature. The proposed CTAT and PTAT sensors are implemented on silicon using a typical 0.18μm CMOS process. The core area of the CTAT and PTAT sensors is 0.0125mm2 and 0.0074mm2, respectively. In the range from −55°C to 155°C, the worst deviation of the CTAT and PTAT temperature sensors is measured to be −3.75°Cto+3.34°C and −3.73°Cto+3.85°C, respectively. The maximum non-linearity reduction of the CTAT and PTAT sensors is 59.84% and 87.48%, respectively, by the proposed second-order calibration. Notably, the overhead area of the CTAT and PTAT sensors is only 0.64% and 1.08%, respectively.