| 摘要 |
PURPOSE: A dynamic random access memory device having a self-refresh mode is provided to stabilize sensing margin and to maintain the level of a bit line precharge voltage regardless of the variation of a source voltage during a power down self refresh operation. CONSTITUTION: The dynamic random access memory device having the self-refresh mode includes a pair of bit lines, at least one memory cell, a source voltage provider and a precharger. The memory cell includes a capacitor and a transmission transistor storing data signal and the voltage level of the stored data signal tends to be ground voltage. The source voltage provider provides a source voltage(Vent) of first level during normal operation and a source voltage(Vrefresh) of second level which is lower than the first level. The precharger precharges the bit line pairs by using the voltage from the source voltage provider when a refresh control signal(PSRAS) is activated. The precharger generates the first precharge voltage(Vbl1) of a level corresponding to a half of Vrefresh when the Vrefresh is provided and the second precharge voltage(Vbl3) of a level between the voltage(Vbl2) which is half of the Vent and the first precharge voltage(Vbl1).
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