A Sub-1 V Capacitively Biased BJT-Based Temperature Sensor With an Inaccuracy of ± 0.15 ∘ C (3 σ ) From − 55 ∘ C to 125 ∘ C

A Sub-1 V Capacitively Biased BJT-Based Temperature Sensor With an Inaccuracy of ± 0.15 ∘ C (3 σ ) From − 55 ∘ C to 125 ∘ C

Tang, Z. (TU Delft Electronic Instrumentation; Vango Technologies Inc., Hangzhou)
Pan, S. (TU Delft Electronic Instrumentation; Tsinghua University)
Grubor, M. (TU Delft Electronic Instrumentation; Analog Devices)
Makinwa, K.A.A. (TU Delft Microelectronics)

Microelectronics

2023

This article presents a sub-1 V bipolar junction transistor (BJT)-based temperature sensor that achieves both high accuracy and high energy efficiency. To avoid the extra headroom required by conventional current sources, the sensor’s diode-connected BJTs are biased by precharging sampling capacitors to the supply voltage and then discharging them through the BJTs. This capacitive biasing technique requires little headroom ( ∼ 150 mV), and simultaneously samples the BJTs’ base–emitter voltages. The latter are then applied to a switched-capacitor (SC) ΔΣ ADC to generate a digital representation of temperature. For robust sub-1 V operation and high energy efficiency, the ADC employs auto-zeroed inverter-based integrators. Fabricated in a standard 0.18- μ m CMOS process, the sensor occupies 0.25 mm 2 and consumes 810 nW from a 0.95-V supply at room temperature. It achieves an inaccuracy of ± 0.15 ∘ C (3 σ ) from − 55 ∘ C to 125 ∘ C after a 1-point trim, which is at par with the state-of-the-art. It also achieves a resolution figure of merit (FoM) of 0.34 pJ ⋅ K 2 , which is more than 6 × lower than that of state-of-the-art BJT-based sensors with similar accuracy.

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capacitively biased bipolar junction transistor (BJT)
Capacitors
Energy efficiency
inverter-based amplifier
Mathematics
Switches
Switching circuits
temperature sensor
Temperature sensors
temperature to digital converter
Voltage

http://resolver.tudelft.nl/uuid:658e90b7-5846-4875-a723-9e947860c5a2

https://doi.org/10.1109/JSSC.2023.3308554

2024-05-28

0018-9200

IEEE Journal of Solid State Circuits, 58 (12), 3433-3441

Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.

Institutional Repository

journal article

© 2023 Z. Tang, S. Pan, M. Grubor, K.A.A. Makinwa