US Patent 7206236 Array redundancy supporting multiple independent repairs

Arrays such as SRAMs, DRAMs, CAMs & Programmable ROMs having multiple independent failures are repaired using redundant bit lines. A first embodiment provides redundant bit lines on one side of the array. During a write, data is shifted towards the redundant bit lines on the one side of the array, bypassing failed bit lines. A second embodiment provides a spare bit line on each side of the array. During a write, a first failing bit line is replaced by a first spare bit line on a first side of the array, and a second failing bit line is replaced by a second spare bit line on a second side of the array.