The mode switching circuit 1200 may output the first enable signal EN_1 or the second enable signal EN_2 depending on a mode of an electronic device (e.g., a memory device) including the data buffer 1000. The mode switching circuit 1200 typically does not simultaneously activate and output the first and second enable signals EN_1 and EN_2. The first and second enable signals EN_1 and EN_2 may be output depending on a swing level of the input data DATA_IN. The data transmission circuit 110 may operate in a particular mode depending on the first or second enable signal EN_1 or EN_2.

When the input data DATA_IN has a first swing level, the mode switching circuit 1200 may output the first enable signal EN_1. At this time, the second enable signal EN_2 may be inactivated.

FIG. 2 is a diagram illustrating data modes in which swing levels of data are different from each other according to an embodiment of the present disclosure.