Patent ID: 8890216

Claim:
A chemical detection device, comprising: a substrate of a first semiconductor type; a column of chemical detection pixels, each chemical detection pixel including: a chemically-sensitive transistor formed in the substrate, each chemically-sensitive transistor having a first terminal and a second terminal; and a first switch formed in the substrate; and a readout circuit, including: a first operational amplifier formed in the substrate coupled to a supply voltage, the first operational amplifier having a first input and a first output, the first input being coupled to the first terminal of the chemically-sensitive transistor of each chemical detection pixel of the column via the first switch of the respective pixel; a second operational amplifier formed in the substrate coupled to the supply voltage, the second operational amplifier having a second input and a second output, the second output coupled to the second terminal of the chemically-sensitive transistor of each chemical detection pixel of the column; a first transistor having first and second terminals coupled to the first output and second input respectively; and a current sink coupled between the second input and the supply voltage.