US Patent 7881130 Semiconductor memory device having write data through function

A semiconductor memory device includes a switch that turns on or off connection between a write data line pair which is an output of a write buffer and read data line pair. For a Write Data Through function, the switch is turned on in response to an activated one-shot pulse and a sense amplifier activation signal, thereby approximately equalizing data hold time tOHW in the Write Data Through function and data hold time tOHR in a read operation.