According to an embodiment, a semiconductor device includes a differential input circuit suitable for receiving first and second input signals respectively inputted to first and second input transistors, and outputting an output signal; a comparison circuit suitable for generating a first judge signal by comparing the output signal with a first comparison voltage, and generating a second judge signal by comparing the output signal with a second comparison voltage, in a calibration mode; an offset control circuit suitable for adjusting coarse codes and fine codes, according to the first and second judge signals; and an offset adjusting circuit suitable for adjusting a drivability of each of the first and second input transistors by a first strength, according to the coarse codes, and adjusting the drivability of each of the first and second input transistors by a second strength smaller than the first strength, according to the fine codes.