Temperature Sensor Front End in SOI CMOS Operating up to 250

TLDR: The proposed Vth extraction circuit eliminates the nonlinear temperature-dependent mobility and mobility ratio terms, and it achieves a wide operating temperature range from -25 °C to 250 °C, and the ratiometric output achieves mean temperature inaccuracy within ±1.8% over a temperature of 275 °C.

Abstract: This brief presents a complementary-to-absolute-temperature voltage and a voltage reference based on the threshold voltage Vth extraction principle. The proposed Vth extraction circuit eliminates the nonlinear temperature-dependent mobility and mobility ratio terms, and it achieves a wide operating temperature range from -25 °C to 250 °C. The threshold-voltage temperature coefficient (TC) mismatch between nMOS and pMOS is compensated by selecting different channel lengths. Fabricated in the 1-μm partially depleted silicon-on-insulator CMOS process, the voltage reference achieves a box model TC of 27 parts per million (ppm) (mean) for an operating temperature range of -25 °C-250 °C and 18.7 ppm (mean) for a range of 25 °C-150 °C. Furthermore, the ratiometric output achieves mean temperature inaccuracy within ±1.8% over a temperature of 275 °C.