Design and characterization of a 5-decade range integrated resistive gas sensor interface with 13-Bit A/D converter

In this paper we present the design and testing of an integrated wide-range interface for resistive sensors. The ASIC consists of a multi-scale trans-resistance continuous time amplifier (programmed by selecting a feedback resistor from an array), followed by a 13-bit incremental A/D converter. After calibration, employed to cancel offset and gain error mismatch between scales, the device shows a worst case error in the resistance value measurement of about 0.1% over a range of more than 5 decades [100 Omega-20M Omega]