New CMOS potentiostat as ASIC for several electrochemical microsensors construction

摘要

Purpose – The purpose of this paper is to design and create a potentiostat that can be integrated and encapsulated within a microelectrode as a lowcost electrochemical sensor. Recently, microsystems on sensors or lab on a chip using electrochemical detection of substances matters are pushing forward into the area of analysis. For providing electrochemical analysis, the microsystem has to be equipped with an integrated potentiostat.Design/methodology/approach – The integrated potentiostat with four current ranges (from 1mA to 1 mA) was designed in the CADENCE software environment using the AMIS CMOS 0.7mm technology and fabricated under the Europractice program. Memory cells of 48 bytes are implemented with the potentiostat using VERILOG. Findings – The characteristics of integrated potentiostat are strictly linear; the measured results confirm the simulated values. The potentiostat measurements error is about 1.5 percent and very low offsets are reached by the offset-zeroing circuitry. Research limitations/implications – The detection limit of the current at the lowest range with respect to S/N ratio is about 10 nA. Practical implications – The integrated potentiostat is embedded on a screen-printed sensor and its characteristics are successfully verified. Lower range of 100 nA can be implemented on a new microchip as well as rail-to-rail output circuitry would increase the voltage dynamic range. Originality/value – The integrated potentiostat with very good parameters is designed for a wide spectrum of electrochemical applications such as lab on a chip, embedded electrochemical systems, etc. The integrated system enables storing of information about the system measured, for instance, calibration and fabrication data of the electrochemical sensor.