A 0.1% accuracy 100/spl Omega/-20M/spl Omega/ dynamic range integrated gas sensor interface circuit with 13+4 bit digital output

Abstract

This paper presents the design and the characterization of an integrated wide-range interface circuit for resistive sensors. The device is actually a multi-scale transresistance continuous time amplifier followed by a 13-bit incremental A/D converter. As shown in measurements the worst case resolution is near to 0.1% over a range of 5.3 decades [100/spl Omega/-20M/spl Omega/] thanks to a calibration technique which cancels offset and gain error mismatch between scales. The chip has been designed in 0.35/spl mu/m CMOS technology.