Fig. 3: Design and performance of the CMOS circuit.

a Design of the CMOS circuit structure. b Peripheral testing circuit structure. c CMOS circuit layout. d CMOS circuit chip, including a heating circuit and resistance-to-voltage circuit. e Multichannel cyclic testing results of the biomimetic intelligent olfactory sensing system. f Test results from Channels 2, 8, and 15 for the different concentrations of methanol. g Response results from the 16-channel gas sensors to different types of gases