Semiconductor memory device and operation method thereof

1. A semiconductor memory device comprising:

an information generation unit configured to convert positions of threshold voltages of memory cells in threshold voltage distributions based on determination voltages included in an overlapping portion between the threshold voltage distributions to generate a plurality of position information codes; and

an error correction unit configured to sequentially receive the plurality of position information codes and perform an error correction operation for data of the memory cells.

2. The semiconductor memory device of claim 1 , wherein the determination voltages comprise two or more reference voltages between threshold voltages distributions overlapping and corresponding to different least significant bit data or different most significant bit data, among the data of the memory cells.

3. A semiconductor memory system comprising:

a memory unit configured to convert positions of threshold voltages of memory cells in threshold voltage distributions into a plurality of position information codes in response to determination voltages included in an overlapping portion between the threshold voltage distributions and sequentially output the plurality of position information codes in response to a read command;

an error correction unit configured to perform an error correction operation on the plurality of position information codes for data of the memory cells; and

a control unit configured to generate the read command in response to an output signal of the error correction unit.

4. The semiconductor memory device system of claim 3 , wherein the control unit receives and processes the data of the memory cells outputted from the memory unit.

5. The semiconductor memory device system of claim 3 , wherein the determination voltages comprise two or more reference voltages between threshold voltages distributions overlapping and corresponding to different least significant bit data or different most significant bit data, among the data of the memory cells.

6. An operating method of a semiconductor memory device, comprising:

setting a plurality of determination voltages in an overlapping portion between threshold voltage distributions;

converting a position of a threshold voltage of a memory cell in the threshold voltage distributions into a plurality of position information codes based on the plurality of determination voltages;

performing an error correction operation on one position information code among the plurality of position information codes, in response to a read command; and

detecting whether data of the memory cell is normal or not, depending on a result from the performing of the error correction operation.

7. The operating method of claim 6 , further comprising:

generating a next read command depending on a result from the detecting of whether the data is normal or not; and

performing an error correction operation on the other position information codes among the plurality of position information codes, in response to the next read command.

8. An operating method of a semiconductor memory device, comprising:

setting first to third determination voltages in an overlapping portion between threshold voltage distributions, wherein the first to third determination voltages are in order from the lowest to the highest;

determining a position of a threshold voltage of a memory cell in the threshold voltage distributions based on the second determination voltage to generate a first position information code;

determining the position of the threshold voltage based on the first and third determination voltages to generate a second position information code; and

sequentially receiving the first and second position information codes to perform an error correction operation for data of the memory cell.

9. The operating method of claim 8 , wherein the determining of the position of the threshold voltage based on the second determination voltage comprises:

determining whether the threshold voltage is lower or higher than the second determination voltage.

10. The operating method of claim 8 , wherein the determining of the position of the threshold voltage based on the first and third determination voltages comprises:

determining whether the threshold voltage is between the first and third determination voltages or not.

11. The semiconductor memory device of claim 8 , wherein the first to third determination voltages are set in an overlapping portion between threshold voltages distributions overlapping and corresponding to different least significant bit data or different most significant bit data, among the data of the memory cells.