An input buffer includes a first buffer, a feedback circuit and a second buffer circuit. The feedback circuit includes a feedback resistor and a feedback inverter. The first buffer may be configured to output an amplification signal to an output node of the first buffer based on an input signal. The feedback circuit connected to the output node of the first buffer may be configured to control the amplification signal. The second buffer circuit may be configured to output a buffer output signal by buffering the amplification signal. The feedback resistor may receive the amplification signal from the output node of the first buffer and provide a feedback signal to a feedback node. The feedback inverter is connected between the feedback node and the output node. The feedback inverter may be configured to control the amplification signal based on the feedback signal.