An Untrimmed BJT-Based Temperature Sensor With Dynamic Current-Gain Compensation in 55-nm CMOS Process

This brief presents a bipolar junction transistor (BJT)-based CMOS temperature sensor without trimming. A current-mode readout scheme with dynamic current gain compensation is proposed to reduce the error caused by the low current gain beta of the substrate BJT in nanometer CMOS technologies. Combining this readout scheme with techniques, such as chopping and dynamic element matching (DEM), the sensor achieves a high untrimmed accuracy for auto-calibration in thermal management applications. Fabricated in a standard digital 55-nm CMOS process, the sensor shows a measured inaccuracy within +/- 1.7 degrees C (3 sigma) from -40 degrees C to 125 degrees C without calibration. It occupies a die area of 0.0146 mm(2) and has a power consumption of 37 mu W with an adjustable resolution from 12 to 15 bit and a conversion time of 4.1-32.8 ms.