Word group redundancy scheme

摘要

A word redundancy scheme for a high speed RAM where the bit output stage uses on-chip logic. An extra emitter on each of the decoders is utilized including redundant word group decoders. A compare circuit has an output to each of the extra emitters and when the address of a bad bit arrives at the compare circuit it de-selects each of the non-redundant decoders at that address and selects the redundant decoders via the extra emitters. Hence, the redundant decoders replace the decoders of the bad bit position.