Non-volatile memory device with threshold voltage control function

摘要

Even when the number of rewrite operations varies among erase unit areas, the number of rewrite operations is improved for all of the erase unit areas. A flash EEPROM 100 comprises a trimming value storing area 130 of storing a trimming value corresponding to each erase unit area 120 included in a memory cell array 110 . When an erase operation and a write operation are performed with respect to a certain erase unit area 120 , a regulator circuit 150 converts a voltage boosted by a booster circuit 140 to a level corresponding to the trimming value for the erase unit area 120 . When a read determination circuit 170 detects an abnormality as the number of rewrite operations is increased, the trimming value is updated to a value which causes the regulator circuit 150 to increase the output voltage.