An 88.6nW ozone pollutant sensing interface IC with a 159 dB dynamic range

This paper presents a low power resistive sensor interface IC designed at 0.6V for ozone pollutant sensing. The large resistance range of gas sensors poses challenges in designing a low power sensor interface. Exiting architectures are insufficient for achieving a high dynamic range while enabling low V_DD operation, resulting in high power consumption regardless of the adopted architecture. We present an adaptive architecture that provides baseline resistance cancellation and dynamic current control to enable low V_DD operation while maintaining a dynamic range of 159dB across 20kΩ-1MΩ. The sensor interface IC is fabricated in a 65nm bulk CMOS process and consumes 88.6nW of power which is 300x lower than the state-of-art. The full system power ranges between 116 nW - 1.09 μW which includes the proposed sensor interface IC, analog to digital converter and peripheral circuits. The sensor interface's performance was verified using custom resistive metal-oxide sensors for ozone concentrations from 50 ppb to 900 ppb.