AN INTERFACE CIRCUITRY FOR CMOS-COMPATIBLE, MICROMACHINED-CHEMICAL SENSOR ARRAYS

摘要

This paper describes a full custom, mixed-signal design of a low power interface circuitry for micromachined-chemical gas sensors using AMS 0.35μm CMOS technology. The interface circuitry includes a read-out circuitry, heater control circuitry, Analog-to-Digital Converter (ADC) and Digital-to-Analog Converter (DAC). Low power consumption, being parallel and fast, flexible configuration for a higher resolution output, and wide measurement range are the advantages of this design. The interface circuitry is designed for a 2x4 gas sensor array, based on metal-oxide, resistive-type sensing elements such as SnO_x, ZnO and TiO_2. The design is also compatible with larger-array-sized gas sensor arrays at the expense of a larger chip-area and higher power consumption.