An all-digital CMOS temperature sensor with a wide supply voltage range

This paper proposes a MOSFET-based all-digital temperature sensor fabricated in standard 55-nm CMOS process. The sensing elements of the are composed ring oscillators, which convert information into frequency information. ratio’s proportional to absolute (PTAT) feature is generated by using two separate oscillators with varied sensitivity. frequency-to-digital converter (FDC) converts digital representation without introducing any overhead reference clock. A die area 1915µm2 occupied, owing architecture. After two-point calibration, proposed achieves an error -0.4°C∼+0.6°C throughout range -40°C∼125°C. With help class-adjustable can function wide supply voltage from 0.5V 1.2V. It obtains resolution 0.166°C at room dissipation 2.5µW.