An Energy-Efficient BJT-Based Temperature Sensor with ±0.8 °C (3σ) Inaccuracy from −50 to 150 °C

Abstract

This article presents an energy-efficient BJT-based temperature sensor. The output of sensing front-ends is modulated by employing an incremental Δ-Σ ADC as a readout interface. The cascoded floating-inverter-based dynamic amplifier (FIA) is used as the integrator instead of the conventional operational transconductance amplifier (OTA) to achieve a low power consumption. To enhance the accuracy, chopping and dynamic element matching (DEM) are applied to eliminate the component mismatch error while β-compensation resistor and optimized bias current are used to minimize the effect of β variation. Fabricated in a standard 180-nm CMOS process, this sensor has an active area of 0.13 mm2. While dissipating only 45.7 μW in total, the sensor achieves an inaccuracy of ±0.8 °C (3σ) from −50 °C to 150 °C after one-point calibration.