An image sensor device includes a first image pixel connected to a first data line, a second image pixel connected to the first data line, an analog-to-digital converter that generates a digital signal based on a ramp signal and a voltage level of the first data line, and a clamp signal generator that generates a clamp signal depending on an analog gain of the analog-to-digital converter. While a data voltage is provided from the first image pixel to the first data line, the second image pixel provides a clamp voltage to the first data line based on the clamp signal.