Temperature Sensor Front End in SOI CMOS Operating up to 250°C

This brief presents a complementary-to-absolute-temperature voltage and a voltage reference based on the threshold voltage V-th extraction principle. The proposed V-th extraction circuit eliminates the nonlinear temperature-dependent mobility and mobility ratio terms, and it achieves a wide operating temperature range from -25 degrees C to 250 degrees C. The threshold-voltage temperature coefficient (TC) mismatch between nMOS and pMOS is compensated by selecting different channel lengths. Fabricated in the 1-mu m 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 degrees C-250 degrees C and 18.7 ppm (mean) for a range of 25 degrees C-150 degrees C. Furthermore, the ratiometric output achieves mean temperature inaccuracy within +/- 1.8% over a temperature of 275 degrees C.