SEMICONDUCTOR MEMORY DEVICE

摘要

PURPOSE: A semiconductor memory device is provided to sufficiently secure the read margin of an external controller by tuning an AC parameter within a preset range according to a stack package mode. CONSTITUTION: A control signal generating unit(110) generates a plurality of control signals corresponding to a stack package mode in response to an address and a command. An internal circuit tunes an AC parameter in response to the plurality of the control signals. A delay locked loop(120) generates a delay locked clock signal by delaying an external clock signal according to the plurality of the clock signals. A data strobe signal generating unit generates a data strobe signal in response to a delay locked clock signal.