Abstract: An input buffer capable of achieving quick response. The input buffer includes first and second direct-current (DC) voltage controllers and first and second drivers. The first and second DC voltage controllers generate first and second alternating current (AC) signals having AC voltage components of the buffer input signal reflected thereon, respectively. The first driver drives the voltage level of a buffer output signal to the level of a first voltage, that is, a power supply voltage, in response to the first AC signal. The second driver drives the voltage level of a buffer output signal to the level of a second voltage, that is, a ground voltage, in response to the second AC signal. The first and second AC signals respond to a buffer input signal quickly. The first and the second drivers drive the levels of the buffer output signal to the power supply voltage level and the ground voltage level quickly and by a large amount.