12.7 A 0.85V 600nW all-CMOS temperature sensor with an inaccuracy of ±0.4°C (3σ) from −40 to 125°C

This paper describes an all-CMOS temperature sensor intended for RFID applications that achieves both sub-1V operation and high accuracy (±0.4°C) over a wide temperature range (-40 to 125°C). It is also an ultra-low-power design: drawing 700nA from a 0.85V supply. This is achieved by the use of dynamic threshold MOSTs (DTMOSTs) as temperature-sensing devices, which are then read out by an inverter-based 2^nd-order zoom ADC. Circuit errors are mitigated by the use of dynamic error-correction techniques, while DTMOST spread is reduced by a single room temperature (RT) trim. The latter feature constitutes a significant advance over previous all-CMOS designs [5,6], which require two-point trimming to approach the same level of accuracy.