An Ultra-High Linear Digitization Temperature Sensor Based on SAR ADC With Common-Mode Temperature Drift Suppression
Hang Liu, Yuying Li, Haoyuan Shen, Bo Wu, Yu Jin, Duli Yu, Heming Sun
Abstract
A BJT-based CMOS temperature sensor with an extremely wide temperature range is presented. A voltage mode read-out circuit structure based on common-mode temperature drift suppression technique is proposed to reduce the error caused by the high temperature drift of the read-out circuit in the CMOS process. By analyzing the ratiometric measurement scheme of the temperature sensor, a high sensitivity and high linearity common-mode temperature suppression structure is proposed to ensure the regular operation of the read-out circuit. It makes the structure more robust and expandable, and is suitable for the voltage domain temperature sensor read-out systems. The prototype of the sensor, implemented in a 180nm CMOS process, shows a measured inaccuracy within ±1°C ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$3\sigma$ </tex-math></inline-formula> ) from −40°C to 175°C with 1-point calibration and temperature sensing ultra-linearity <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$R^{2}$ </tex-math></inline-formula> is more significant than 0.99. It occupies a die area of 0.42mm2 and consumes 0.3 mW with a medium resolution 12 bit and a fast conversion time of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10 ~\mu \text{s}$ </tex-math></inline-formula> .