Gas recognition circuits for integrated CMOS electronic noses

[Truncated abstract] Over the past decade, machine olfaction has made signi cant progress in: (i) gas sensing technology with a variety of new materials and detection prin- ciples proposed; (ii) processing of the gas sensor array data for improved gas detection and identi cation; and (iii) understanding and modeling of the ol- factory pathway with the 2004 Nobel Prize in Physiology or Medicine awarded to Richard Axel and Linda Buck for their work on the olfactory system. In spite of these signi cant advances, commercial electronic nose systems have achieved only limited success, due to their high cost, large size, slow response, drift, limited selectivity and speci city, all of which prevent their large-scale deployment for environment and industrial monitoring, security applications, to name a few. Many of these problems could be addressed by fabricating electronic noses using the currently dominant and well-established technology for integrated circuits, which is CMOS (Complementary Metal Oxide Semicon- ductor) technology. Use of a semiconductor substrate, such as silicon, opens the possibility of integrating electronics with the sensor array on a single silicon chip to reduce size and noise, improve manufacturing control and enable batch fabrication of the whole electronic nose system at low costs and industrial standards. However, the co-integration of sensor and circuitry has been so far limited to on-chip signal ampli cation, conditioning and/or analog-to-digital conversion.