An image sensor array includes pixels arranged in rows and columns, wherein each pixel includes a transistor serially coupled to a photodiode, data lines coupled to a first node of the pixel, bias lines coupled to a second node of the pixel, gate lines coupled to a third node of the pixel, and electrostatic-discharge (ESD) circuits coupled between the gate lines and an ESD bus, wherein the ESD circuits each include first and second metal oxide offset bottom gate transistors in parallel connection.