METHOD OF READING MEMORY CELLS WITH DIFFERENT THRESHOLD VOLTAGES WITHOUT VARIATION OF WORD LINE VOLTAGE AND NONVOLATILE MEMORY DEVICE USING THE SAME

A soft-decision read method of a nonvolatile memory device includes receiving a soft-decision read command, applying a read voltage to a selected word line, pre-charging bit lines respectively connected to selected memory cells of the selected word line, continuously sensing states of the selected memory cells. The pre-charged voltages of the bit lines and the read voltage supplied to the selected word line are not varied during the sensing states of the selected memory cells.