A BJT-Based Fully Integrated 16-bit ZOOM Temperature Sensor with an Inaccuracy of 0.28°C (3σ) from -40°C to 125°C using improved 1-point Calibration

This paper describes a temperature sensor with a 16-bit Zoom Analog-to-Digital (ADC) intended for Internet-of-Things (IoT). It uses a BJT-based front-end to generate a proportion related to temperature, relying on the PTAT and CTAT properties. Noise cancellation technique and dynamic element matching (DEM) are used to decrease the effect of non-ideal factors while a guard-band method is proposed to improve the conversion accuracy of Zoom ADC. The prototype sensor is fabricated in a 55nm CMOS process and occupies a core area of 0.083 mm
²
. The sensor achieves an inaccuracy of only 0.28 °C (3σ) from −40°C to 125°C with the help of the improved 1-point calibration. Operating at 1.2V supply, it consumes 9.9μW and obtains a resolution of 10mk in a 10.68ms conversion time, showing a figure-of-merit (FOM) of 10.61 pJ·K
²
.