SEMICONDUCTOR MEMORY DEVICE HAVING TWO STAGE INPUT BUFFER

摘要

A semiconductor memory device having a two-stage input buffer is provided to assure setup/hold time margin stably regardless of PVT(Process, Voltage, Temperature) variation. A preamplifier unit(100) outputs a pre-output signal by amplifying level difference between a reference voltage and an input signal. A delay unit(200) outputs an input-delay signal by delaying the input signal. A main amplifier unit(300) outputs an output signal by receiving the pre-output signal and the input-delay signal automatically. The delay unit is a transfer gate outputting the input-delay signal with phase difference of 180 degrees from the pre-output signal, by delaying the input signal as much as operation time of the preamplifier unit.