A data receiver includes a first buffer circuit and a second buffer circuit. The first buffer circuit varies a resistance of a data path and a resistance of a reference voltage path based on a plurality of control signals, and adjusts a voltage level of an input data signal and a level of a reference voltage to generate an internal data signal and an internal reference voltage based on the varied resistance of the data path and the varied resistance of the reference voltage path. The second buffer circuit compares the internal data signal with the internal reference voltage to generate a data signal.