Non-volatile semiconductor memory device and memory system using the same

摘要

The time required for the program verify and erase verify operations can be shortened. The change of threshold values of memory cells can be suppressed even if the write and erase operations are executed repetitively. After the program and erase operations, whether the operations were properly executed can be judged simultaneously for all bit lines (BL) basing upon a change, after the pre-charge, of the potential at each bit line (BL), without changing the column address. A collective verify signal is output when each bit of a page of data has been written into the memory.