An on-chip temperature sensor with 0.5 °C resolution and 0.34% linearity error using 180-nm CMOS process

Abstract

This investigation demonstrates an on-chip temperature sensor with a maximum linear error less than 0.4% and 0.5 °C resolution. The design comprises Current-to-Frequency Converters (CFC), complementary (CTAT), and proportional (PTAT) to absolute temperature current generator circuits. Most important of all, the proposed sensor is featured with the ratio of these two currents to enhance the linearity and high resolution. The proposed sensor was realized using a 180-nm CMOS process. The core area is 0.196 mm${}^2$. The measurement results show 0.3484% maximum linearity error for the PTAT/CTAT ratio. The maximum output frequency of the temperature detector is 4.817 MHz, with the highest power consumption of 20.13 mW. It was proved to be used in a –40 °C$\sim$100 °C temperature detection range with 0.5 °C resolution.