Circuit for cancelling and replacing redundant elements

摘要

In an integrated circuit having addressable primary elements and redundant elements which can be programmed to replace primary elements, a circuit and method are provided for cancelling and replacing redundant elements. A circuit is described which can be used in a memory such as a dynamic random access memory (DRAM) which uses a selectively blowable anti-fuse to disable a redundant element which was previously programmed to replace a defective primary element. The disclosure describes a method for permanently cancelling the defective redundant element and replacing the defective redundant element with another redundant element.