| 摘要 |
PURPOSE: A memory system and a reading method thereof are provided to improve the efficiency of a reading operation by setting the level of a read voltage applied to a memory cell according to the number of bits of data stored in a memory cell. CONSTITUTION: A nonvolatile memory device includes a first memory cell block group in which an LSB program operation is performed, a second memory cell block group in which the LSB program operation and a CSB program operation are performed, and a third memory cell block group in which the LSB program operation, the CSB program operation, and an MSB program operation are performed. A memory controller(190) checks the memory cell group which a memory cell block selected by an address signal belongs to. The main controller sets a read voltage for the LSB data reading operation, the CSB data reading operation or MSB data reading operation of the memory cell block selected according to a confirmation result. |
