23.5 A Sub-1V 810nW Capacitively-Biased BJT-Based Temperature Sensor with an Inaccuracy of ±0.15°C (3σ) from −55°C to 125°C
Zhong Tang, Sining Pan, Kofi A. A. Makinwa
Abstract
BJT-based temperature sensors are widely used because they can achieve excellent accuracy after 1-point calibration. However, they typically dissipate <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mu \text{Ws}$</tex> of power and require supply voltages above 1V [1]. Although sensors based on DTMOSTs [2], [3], capacitively biased (CB) diodes and BJTs [4,5] have demonstrated sub-1V operation, this comes at the expense of accuracy. This paper presents a sub-1V CB BJT-based temperature sensor that achieves a 1-point-trimmed inaccuracy of 0.15°C (3σ) from <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$-55^{\circ}\mathrm{C}$</tex> to <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$125^{\circ}\mathrm{C}$</tex> , which is <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$4\times$</tex> better than the CB BJT state-of-the-art [4]. It also achieves a resolution FoM of 0.34pJ.K <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , which is 6.8 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\times$</tex> better than that of state-of-the-art BJT-based sensors with a similar accuracy [1], [6], (Fig. 23.5.6).