| 摘要 |
<p>A reference apparatus capable of handling the multi-level data while establishing sufficient correlation with memory cells, without increasing the area of the circuits. The reference apparatus is provided with a pluraltiy of reference cells sets each of which comprises a reference cell having a gate coupling ratio smaller than that of the memory cells, and a reference cell having a gate coupling ratio larger than that of the memory cells. The reference cells sets are programmed according to the number of pulses which is an integral multiple of the number of program pulses fed to the memory cells or according to the time that corresponds to the number of pulses, whereby a reference level is set.</p> |
