| 摘要 |
PURPOSE: To provide a non-volatile semiconductor memory in which the influence of dispersion of gm of a memory cell is reduced and which can perform high speed read-out. CONSTITUTION: A main body cell MC of a memory cell array 1 is connected to the sense node SN of a comparator 31 through a bit line BL. Reference cells RC01-RC03, RC11-RC13, RC21-RC23 of a reference current source circuit 32 are selected by a changeover switch circuit 33 and connected to the reference node RN of the comparator 31. In a normal read operation, read voltage is applied to the control gate of the main body cell MC and the control gates of the reference cells RC03, RC13, RC23 of the reference current source circuit 32, reference current values for read-out Iread01, Iread12, Iread23 are compared with a cell current. In verify-read operation at the time of write, any of reference cells RC01, RC02, RC11, RC12, RC21 and RC22 is selected in accordance with write data and the same voltage as that at the time of the read operation is given, and a reference current value Iverify for verify-read is compared with a cell current.
|
