US Patent 7336536 Handling defective memory blocks of NAND memory devices

Apparatus and methods are provided. A NAND memory device has a memory array comprising a plurality of memory blocks and a volatile latch coupled to each of the memory blocks for selectively preventing testing of the respective memory block coupled thereto when that memory block is a known defective block. A non-volatile latch may also be coupled to each of the memory blocks for permanently preventing access, during normal operation of the memory device, to the respective memory block coupled thereto when that memory block is a known defective block.