A CMOS temperature sensor with a voltage-calibrated inaccuracy of ±0.15°C (3σ) from −55 to 125°C

This paper describes an energy-efficient CMOS temperature sensor intended for use in RFID tags. The sensor achieves an inaccuracy of ±0.15°C (3σ) over the military temperature range (-55 to 125°C) and dissipates only 27nJ/conversion: over 20× less than a previous sensor with comparable accuracy and resolution [2]. This energy efficiency is achieved by the use of an improved charge-balancing scheme and a zoom ADC that combines a 5b coarse SAR conversion with a 10b fine 2^nd-order ΔΣ conversion.