| Title |
A BJT-based CMOS Temperature Sensor With a ±0.94?C 3σ -inaccuracy From ?40?C to +150?C |
| Authors |
(Tae-June Park) ; (Jun-Ho Boo) ; (Jae-Geun Lim) ; (Hyoung-Jung Kim) ; (Jae-Hyuk Lee) ; (Seong-Bo Park) ; (Won-Jun Cho) ; (Gil-Cho Ahn) |
| DOI |
https://doi.org/10.5573/JSTS.2025.25.3.236 |
| Keywords |
BJT; β-compensation technique; bitstream-controlled dynamic element matching (DEM); systemlevel low-frequency chopping (CHL); temperature sensor |
| Abstract |
This paper presents a BJT-based CMOS temperature sensor designed for an extended temperature range.
In the sensing frontend, a β-compensation technique is employed to mitigate the effects of the finite current gain (β) of PNP transistors. Additionally, bitstream-controlled dynamic element matching (DEM) is applied to address mismatch errors in current sources and PNP transistors. The readout circuit based on 1-bit second-order incremental ?Σ ADC is configured with a minimum number of sampling switches to mitigate the impact of increasing switch leakage currents at high temperatures. Furthermore, system-level low-frequency chopping (CHL) is implemented digitally, removing the need for extra switches. Fabricated in a 0.18-μm CMOS process, the proposed sensor occupies an area of 0.63 mm2 . The sensor is accurate to within ±0.94?C (3σ) after one-point trimming from ?40?C to +150?C. It achieves a resolution figure of merit (FoM) of 21.17 pJ·K 2 at 27?C, with a conversion time of 20 ms and a power consumption of 22.23 μW from a 1.8 V supply. |