Patent ID: 6928377
Filing Date: 2005-08-09
Classification: G11C

Abstract:
1. A method for self-testing, allocating and repairing a Random Access Memory (RAM) using a spare data column and spare rows, comprising: performing first and second passes of self-test on the RAM memory; in the first pass of self-test, determining a worst failing column of the RAM memory by testing one data column at a time while counting the number of unique failing row addresses of the tested data column by masking all data columns except the tested data column, such that only the un-masked tested data column produces an error in a data-out comparator; after completion of the first pass of self-test, allocating the spare column to replace the worst failing column; in the second pass of self-test, determining unique failing row addresses in the memory; after completion of the second pass of self-test, allocating the spare rows to replace the failing rows.