| 摘要 |
A non-volatile semiconductor memory device capable of selectively storing one of at least three different data comprises a memory array including a plurality of memory cells, each having a control gate, a floating gate, a drain, and a source, a circuit for producing a stepped voltage whose level is varied stepwise to a number of different levels corresponding to a number of data to be stored, a circuit for producing a pulse voltage having a predetermined voltage level and a predetermined pulse width, and a circuit for selecting one of the plurality of memory cells, wherein during storing of the at least three different data the stepped voltage and the pulse voltage are applied to the control gate and the drain of the selected memory cell, respectively, while a timing of application of the pulse voltage to the drain is controlled relative to a timing of application of the stepped voltage to the control gate, depending on which of the at least three different data is to be stored into the selected memory cell.
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