A device and method for integrated circuits with surrounding gate structures are disclosed. The imaging system has the advantage of providing high relative illumination and high contrast at elevated spatial frequencies even when using a fast aperture. According to functional requirements of the universal IO unit, the pad power is selectively connected to an electric wire to couple to a predetermined voltage, and each of the signal pads is also selectively connected to a signal wire to transceive signals. The first input receives either the input signal or a feedback signal, depending upon mode control signals. An analog-to-digital converter is provided to respectively convert the I signal and the Q signal to digital domain representations of the I signal and the Q signal.