A CMOS potentiostat circuit for parallel direct DNA sensing

摘要

An on-chip CMOS potentiostat, including a triangle wave signal generator, a small current signal detector and a potential controller, and its auxiliary circuits are presented for deoxyribonucleic acid (DNA) sensing applications. A fully differential transimpedance amplifier (TIA) with reconfigurable resistors was used for wide range current measurements. An 8×8 pixel array consisting of a 64-pixel rectangular working electrode array with an optimized reference and counter electrode structure is proposed for testing purposes. The design is based on 0.18 μm CMOS technology with a 1.8 V supply. Post-verification measurements show that the scanning signal generator can generate a triangle wave with a tunable frequency when the voltage changes from 300 mV to 1.69 V. The circuit also achieves a large dynamic range of up to 100 dB, and shows very good linearity from 90 pA to 9 μA.