A delay locked loop (DLL) apparatus includes a first delay unit converting a reference clock into a rising clock. A second delay unit converts the reference clock into a falling clock, and a replica delay unit replica-delays the rising clock. A first phase detector compares the phases of the reference clock and the delayed rising clock to output a first detection signal corresponding to the compared phases. A controller synchronizes the rising edge of the rising clock with the rising edge of the reference clock according to the first detection signal of the first phase detector. A second phase detector compares the phases of the synchronized rising clock and the synchronization clock to output a second detection signal corresponding to the compared phases. The DLL apparatus compensates for a skew between an external clock and data and between external and internal clocks by employing a single replica delay unit.