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

• Published in: IEEE transactions on circuits and systems. II, Express briefs Express briefs, 2019-10, Vol.66 (10), p.1613-1617
• Main Authors: Tang, Zhong, Fang, Yun, Huang, Zhenyan, Yu, Xiao-Peng, Shi, Zheng, Tan, Nick Nianxiong
• Format: Article
• Language: English
• Subjects: Bipolar transistors; BJT; Calibration; Capacitors; CMOS; CMOS process; CMOS temperature sensor; Compensation; current mode; Cutting; dynamic current-gain compensation; Error reduction; Generators; IP networks; Low currents; Modulation; Power consumption; Sensors; Substrates; Temperature sensors; Thermal management
• ISSN: 1549-7747; 1558-3791
• DOI: 10.1109/TCSII.2019.2921889

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 β 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 °C (3σ) from -40 °C to 125 °C without calibration. It occupies a die area of 0.0146 mm2 and has a power consumption of 37 μW with an adjustable resolution from 12 to 15 bit and a conversion time of 4.1-32.8 ms.