SEMICONDUCTOR MEMORY APPARATUS

摘要

PURPOSE: A semiconductor memory device is provided to improve the area efficiency of a semiconductor memory device by combining a delay locked loop circuit with an output enable signal generating circuit as one circuit. CONSTITUTION: An input selection unit(100) outputs one of an input clock and a data output command as a first selection signal and outputs the remaining as a second selection signal. A second delay locked circuit unit(400) outputs a second delay signal by delaying the second selection signal and generates a second feedback signal and a second phase comparison signal. A delay control unit generates a first delay control signal and a second delay control signal in response to a first phase comparison signal and the second phase comparison signal. An output selection unit outputs one of the first delay signal and the second delay signal as a delay locked clock and outputs the remaining as an output enable signal.