3.7 A β-Compensated NPN-Based Temperature Sensor with ±0.1°C (3σ) Inaccuracy from -55°C to 125°C and a 200fJ·K2 Resolution FoM

The two key performance metrics of BJT-based temperature sensors are their accuracy and energy efficiency. Although NPN-based temperature sensors achieve the best energy efficiency [1], they have not been able to combine this with the accuracy of their PNP-based counterparts [2, 3, 4]. This paper presents an NPN-based sensor that achieves both state-of-the-art energy efficiency (200fJ·K
²
FoM) and inaccuracy (0.1°C (3σ) from -55°C to 125°C). It does this by combining a low-noise current-mode front-end with a β-compensation scheme, dynamic-error-correction techniques, and room temperature (RT) calibration. Compared to sensors with high accuracy and energy efficiency [2, 3, 4, 6], the proposed sensor is 2× smaller as well as 2× more energy efficient.