| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent such a demerit that data of a memory cell having a high threshold value due to floating of a ground potential caused by a leak current cannot be read out. SOLUTION: In a memory product of a virtual ground system, pairs of bypass transistor 45-50 for bypassing of current are respectively provided in parallel with transistors for selection selecting this digit line, and this device has a selecting means in which a selection digit line is connected to a sense amplifier 15 responding to column selecting signal y1-y4 and a non-selection digit line is connected to a main virtual ground line L60 or L61 by one side of the pair of bypass transistor. Therefore, a cell potential of a source electrode of a selected memory cell is not floated by a leak current made to flow from an adjacent memory cell, reading out data can be normally performed even for a high threshold value of a multi-memory cell.</p> |
