MEMORY WITH FAULT TOLERANT REFERENCE CIRCUITRY

摘要

A memory ( 10) not only uses redundant cells (16, 18) but also redundant references (120, 122) to reduce the likelihood of a failure. In one approach a failure in a reference (20, 22) can cause both the primary cell (12, 14) as well as the redundant cell (16, 18) to be ineffective. To overcome this potential problem two references (20, 120) for each bit are employed. In one form, the primary cell (12) of a first bit is compared to one reference (20) and the redundant cell (16) of the first bit is compared to another reference (22). The primary (14) and redundant cell (18) of a second bit can use these two references (20, 22) as well.