| 摘要 |
<p>PROBLEM TO BE SOLVED: To shorten a time required for reading out data from a memory cell in which data of (n) levels (n is integer of 4 or more) is stored. SOLUTION: This device is provided with a memory cell array which stores four level data and comprises first and second memory cells, when four level data are discriminated, the four level data are divided into a first read-out and second read-out, the first read-out is performed by respective common 0V for a source potential Vs of the first and the second memory cells, the second read-out is performed by switching a source potential Vs of the first and the second memory cells to 0V or positive potential Vm in accordance with a result of the second read-out.</p> |
