Means for repairing defects in dynamic random access memory, DRAM, modules, where some of the cells have too low residual magnetism

摘要

A dynamic memory module arranged in a matrix (10) of rows and columns has means for testing and localizing defective bits within the matrix and storing the results in a defect memory (24) that has the same number of rows as the matrix (10). Test means are provided to write defect details to the defect memory. In addition an auxiliary memory (22), with as many rows as the matrix (10), is provided and command means (26) are provided to determine access to a defective bit within a selected range of the matrix and link this to the corresponding area of the auxiliary memory using the address data stored in the defect memory (24).