| 摘要 |
A semiconductor memory device and a method thereof are provided to secure a reliable column access operation regardless of an operating frequency change or an environment change by controlling inactivation timing of a column selection signal. A column control signal generating part(410) generates a column access enable signal(YAE) corresponding to a reading command or a writing command. A first delay part(420) delays the column access enable signal as a first delay time. A writing enable generating part(430) generates a writing enable signal(BWEN) corresponding to an output of the first delay part. A second delay part(440) delays the column access enable signal as a second delay time, and outputs a first control signal(Ylore). A third delay part(450) delays the first control signal as a third delay time. A reading enable generating part(460) generates a reading enable signal(IOSTB) corresponding to an output of the third delay part. A column selection signal generating part(480) generates a column selection signal(YI) corresponding to the outputs of the first control signal and the third delay part.
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