| 摘要 |
PURPOSE:To extend a power source voltage margin, by precharging a dummy cell until a memory cell is set to the non-selected state after a sense amplifier is operated and forming stored information of the memory cell and a reference voltage with the same power source voltage. CONSTITUTION:A MOSFETQm is turned on to connect a capacitor Cs to a common data line DL, and a change of the potential of the data line DL which is generated in accordance with the electric charge quantity stored in the capacitor Cs is sensed, thus reading information. This change of the potential of the data line DL due to the electric charge quantity stored in the capacitor Cs appears as a very minute signal. A dummy cell DC is provided as a reference for detection of this minute signal. Even if a considerable variation (bump) is generated in a power source voltage Vcc in the time when a memory array is not selected, the memory cell and the dummy cell hold the storage level and the reference voltage level still in accordance with the power source voltage Vcc in the preceding operation state. |
