Redundant memory circuit and method of programming and verifying the circuit

摘要

A redundant memory circuit having a memory for storing information in a matrix of interconnected rows and columns, and a row and a column address decoder to access the rows and columns. The memory has a redundant row or rows to replace a defective row or rows in the matrix and a programmable decoder which is programmed with the row address of the defective row to access the redundant row. The row and column address decoders are used to access the defective row and to sequentially access the columns so as to entirely disconnect the defective row from the columns. The programmable decoder is then programmed with the defective row address, bit by bit, in response to the column addresses, to access the redundant row. After this procedure, a verification circuit can be used to verify that the redundant row can be accessed and that the programmable decoder is properly programmed to decode only one address to one row.