Double data rate synchronous semiconductor memory device capable of changing data strobe control scheme in package level and method for changing data strobe control scheme for double data rate synchronous semiconductor memory device in wafer level

摘要

PURPOSE: A double data rate SDRAM(Synchronous Dynamic Random Access Memory) capable of changing a data strobe control structure in a packaging level and a method for changing the data strobe control structure of the double data rate SDRAM in a wafer level are provided to reduce the damage by selecting the data strobe control structure suitable for an operation frequency of a DDR(Double Data Rate) SDRAM DRAM in the packaging level. CONSTITUTION: A transistor(205) includes an NMOS(N-type Metal Oxide Semiconductor) transistor. Each of pull-up transistors(210,215,220) includes a PMOS(P-type Metal Oxide Semiconductor) transistor in which an inverse signal(/MRS) of a mode resistor set signal(MRS) is applied to a gate and a power voltage(VDD) is applied to a drain. A transistor(225) includes a PMOS transistor in which the mode resistor set signal(MRS) is applied to a gate and the power voltage(VDD) is applied to a drain. A buffer circuit(230) includes two inverters. Each of OR circuits(235,240,245) includes a NAND gate and an inverter.