A semiconductor device includes a plurality of data driving units, each configured to drive a corresponding data output pad by a power supply voltage supplied through a power supply voltage input pin and a ground voltage supplied through a ground voltage input pin, in response to a corresponding bit of a data code, a pattern sensing unit configured to sense a bit pattern of the data code and generate a pattern sensing signal, and a phantom driving unit configured to form a current path between the power supply voltage input pin and the ground voltage input pin and to drive the current path by a driving force determined in response to the pattern sensing signal.