| 摘要 |
PURPOSE: A NAND-flash memory device is provided to improve speed for data read operation by reducing a time for reading out with sensing multi-bit data at a time. CONSTITUTION: A NAND-flash memory device includes a memory cell array(100), a sensing part(200), a column decoder(300). The memory cell array(100) includes memory cell strings(S0,S1-Sm-1,Sm) where plural flash memory cells are serially connected. The sensing part(200) includes plural sensing circuits(210). Each sensing circuit(210) includes a switching circuit(211), a comparison circuit(212) and a latch circuit(213). Each sensing circuit(210) stores data corresponding to voltage level of sensed current from a common source line(CSL) via the memory cell strings(S0,S1-Sm-1,Sm). Thereby, a time for reading multi-bits data can be reduced so that a speed for data read operation can be improved.
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