A delay locked loop includes a buffer for outputting an internal clock by buffering an external clock, a delay block for delaying the internal clock in response to one of control signals or a selection signal, thereby outputting a delayed clock, a control signal generation block for generating at least one control signal according to a phase difference between the internal clock and a feedback clock generated by delaying the delayed clock by a delay time taken for the internal clock to be output, a selection block for outputting at least one selection signal in response to a signal instructing an off mode of the delay locked loop, thereby controlling a delay time in the delay block, and an output driver for driving the delayed clock.