Memory controller, memory system and operation method thereof

Abstract

A memory controller, a memory system and an operation method thereof are provided. The memory controller can be used to control a memory device, and be configured to search, according to the number of erase cycles of the memory block, for a read retry table corresponding to a range to which the number of erase cycles belongs, when reading fails. The read retry table can include a plurality of read bias groups. The memory controller can further be configured to perform read retry operations on the memory block according to the read bias groups in the read retry table. The read retry table corresponding to the range to which the number of erase cycles of the memory block belongs may be found by index searching with the number of erase cycles, based on the retry read voltages in the optimal read bias group that the memory device has had initially.