US Patent 7577047 Semiconductor memory device

A semiconductor memory device includes a delay time selecting portion for outputting, as a final read/write command, an internal read/write command that corresponds to an external read/write command and is synchronized with an external clock rising edge at a tRCD time without any delay when an address is applied before an address setup time based on the external clock rising edge of a previously set tRCD time, a decoder for decoding an address applied from an external portion with the read/write command to output a decoded address, and a selecting portion for receiving the decoded address to select a memory cell of a memory cell array in response to the final read/write command.