A CMOS smart temperature sensor with a batch-calibrated inaccuracy of ±0.25°C (3σ) from −70°C to 130°C

A major contributor to the total cost of precision CMOS temperature sensors is the cost of trimming and calibration. Significant cost savings can be obtained by batch calibration, but this is usually at the expense of an equally significant loss of accuracy [1]. This paper presents a CMOS temperature sensor with a batch-calibrated inaccuracy of ±0.25°C (3σ) from −70°C to 130°C, which represents a 2× improvement over the state of the art [2]. As in [2], individual trimming reduces the sensor's inaccuracy to ±0.1°C (3σ) over the military range: −55°C to 125°C. The sensor draws 25µA from a 2.5V to 5.5V supply, which is significantly less than commercial products with comparable accuracy [3,4], and 3× less than the sensor reported in [2].