| 摘要 |
PURPOSE:To prevent misreading and to obtain a superior data holding characteristic even if dispersion of a erasing characteristic of a memory cell occurs by providing a source decoder, a source voltage supplying circuit, and a sense amplifier. CONSTITUTION:A source decoder 3 selects one of plural source lines at the time of read-out, a source voltage circuit 2 selectively applies voltage activating a memory cell transistor to a selected source line and applies voltage inactivating a transistor to a source line of non-selection. A sense amplifier 8 has a detecting level by which a current flowing between a drain and a source of a selection memory cell transistor connected to between a selected source line and a selected bit line and a current flowing between a drain and a source of a non-selection memory cell transistor connected to between a selected source line and a selected bit line can be discriminated. Thereby, misreading is prevented even if a memory cell being in a over erasing state exists on a selected bit line. |
