Ultra-low Power CMOS Voltage Reference for High Temperature Applications up to 300°C

A voltage reference circuit dedicated for high temperature applications is presented. A high-temperature operation range up to 300 degrees C and an ultra-low-power consumption of 6 mu A @ 25 degrees C and 18 mu A @ 300 degrees C are achieved by the presented new circuit which is implemented in 0.18 mu m CMOS standard technology occupying layout area of 0.00063 mm(2). The proposed voltage reference is based on the weighted difference of the gate-sources of NMOS and PMOS transistors operating in weak-inversion region. A reference voltage of 1.375 V is obtained with a temperature coefficient of 25 ppm/degrees C in a wide temperature range from 0 degrees C to 280 degrees C and 89 ppm/degrees C @ 300 degrees C. The measured noise densities with a 100nF filtering capacitor are 80 nV/sqrt Hz and 1 nV/sqrt Hz at 100 Hz and 100 kHz respectively, and with a power-supply rejection ration (PSRR) better than -33 dB at 10 MHz.