NONVOLATILE SEMICONDUCTOR MEMORY DEVICE PROGRAMMING SECOND DYNAMIC REFERENCE CELL ACCORDING TO THRESHOLD VALUE OF FIRST DYNAMIC REFERENCE CELL

摘要

In a nonvolatile semiconductor memory device, first and second dynamic reference cells are subjected to a same rewriting operation as performed to a memory cell. An average reference current is obtained from the first and second dynamic reference cells, and is compared with a current of data read from the memory cell so as to judge a level of the read data. In this configuration, the second dynamic reference cell is programmed according to a threshold value of the first dynamic reference cell.