Memory devices having variable repair units therein and methods of repairing same

An operating method of a memory device, comprising:

• receiving a first row address indicating a wordline among first wordlines in a first bank and a second wordlines in a second bank;
• receiving a second row address indicating a wordline among third wordlines in a third bank;
• performing a first repair operation with a first repair unit when the first row address matches stored failed address;
• and
• performing a second repair operation with a second repair unit when the second row address matches stored failed address,
• wherein the performing the first repair operation includes replacing wordlines of the first bank and the second bank with redundant wordlines simultaneously, and the performing the second repair operation includes replacing wordlines of the third bank with redundant wordlines,
• wherein the first repair unit and the second repair unit are different.

A memory system, comprising:

• at least one memory device;
• and
• a controller configured to control the at least one memory device;
• wherein the at least one memory device includes:
• a plurality of banks including memory cells;
• at least one redundant bank including redundant memory cells;
• and
• a repair control circuit configured to perform a repair operation of replacing a part of the memory cells with a part of the redundant memory cells when a row address bits store a failed address;
• wherein the repair control circuit determines that wordlines of one bank of the plurality of banks are replaced or wordlines of two banks of the plurality of banks are replaced simultaneously according to a repair unit of the repair operation,
• wherein the repair unit is flexible according to a type of address bit or the number of the address bits in a test operation.