Memory system and operating method thereof

1. A memory system comprising:

a memory device configured to include a plurality of memory blocks each including memory cells; and

a memory controller configured to calculate numbers of memory cells included in a selected page among the plurality of memory blocks, respectively included in a plurality of threshold voltage regions divided by first read voltages and second read voltages, to determine a read retry set to be used to read data stored in the selected page among a plurality of read retry sets based on the numbers of memory cells respectively included in the plurality of threshold voltage regions, and to control the memory device to perform a read retry operation using the read retry set.

2. The memory system of claim 1 , wherein the memory controller includes:

a memory interface configured to provide a user read command to the memory device; and

a state counter configured to receive first data and second data, which are acquired by read operations on the selected page, based on the first read voltages and the second read voltages.

3. The memory system of claim 2 , wherein the state counter generates a count result by counting the numbers of memory cells respectively included in the plurality of threshold voltage regions divided by the first read voltages and the second read voltages.

4. The memory system of claim 3 , wherein the memory controller further includes:

a status tracker configured to track and generate status information on the plurality of memory blocks, respectively, based on the count result;

a read retry table including the plurality of read retry sets; and

a read retry unit configured to select the read retry set among the plurality of read retry sets based on the status information.

5. The memory system of claim 3 , wherein the status information includes at least one of an erase/write (E/W) cycle count, a read count or temperature information.

6. The memory system of claim 5 , wherein the E/W cycle count includes an E/W cycle count for each memory block included in the memory device.

7. The memory system of claim 5 , wherein the read count includes a read count value for each page of the plurality of memory blocks.

8. The memory system of claim 5 , wherein the temperature information includes information on a temperature measured in the memory device.

9. The memory system of claim 1 , wherein the memory device generates the first read voltages and the second read voltages, based on initial read voltages and first and second offset voltages, in response to a user read command from the memory controller, and outputs first data and second data, which are acquired by read operations on the selected page, based on the first read voltages and the second read voltages.

10. The memory system of claim 9 , wherein the read operations on the selected page include MSB read operations and LSB read operations, and

wherein the first data is generated through one of the MSB read operations and one of the LSB read operations, which are performed based on the first read voltages.

11. The memory system of claim 10 , wherein the one of/each of the MSB read operations is performed using two different voltages among the first read voltages, and one bit is generated from each of multi-bit memory cells.

12. A method for memory controller controlling a memory device including a plurality of memory blocks including memory cells, respectively, the method comprising:

providing a user read command;

receiving first data and second data, which are acquired by read operations on a selected page among the plurality of memory blocks, using first read voltages and second read voltages, in response to the user read command;

counting numbers of memory cells of the selected page respectively included in a plurality of threshold voltage regions divided by the first read voltages and the second read voltages;

selecting a read retry set among a plurality of read retry sets based on the numbers of memory cells; and

controlling the memory device to perform a read retry operation using the read retry set.