Integrated Interface Circuit with Multiplexed Input and Digital Output for a 5x5 SnO2 Gas-Sensor Matrix

This paper presents the design and experimental results for a 5 x 5 tin-oxide gas-sensor array system with particular focus on the employed multiplexed-analog-input 0.35 mum CMOS interface circuit chip. This interface circuit reads the electrical response of all the elements of the array in time sharing by means of a solid-state selector, actually exploiting a row-column query technique and provides digital output to a dedicated Lab View^TM software. The proposed system shows very promising properties in terms of data redundancy in order to improve the Signal-to-Noise-Ratio in electronic nosing and for future studies about the influence of gas consumption rate over the metal oxide surface for a 2-D array.