Method and apparatus for replacing defective rows in a semiconductor memory array

A method for replacing a defective row in a content addressable memory (CAM) array having a plurality of memory block arrays, said arrays having a plurality of normal rows of cells and at least one spare row of cells, each said row being enabled by a corresponding wordline signal, and having corresponding match line outputs switchable to corresponding ones of a plurality of match line inputs in a match line decoder, said method comprising the steps of:

• (a) generating a signal indicative of the location of a defective row in at least one of said arrays;
• (b) generating a set of word line select signals for selecting ones of said plurality of normal rows;
• (c) using said defective row signal to switch a word line select signal of said defective row to a row adjacent said defective row and switching said adjacent row word line select signals to subsequent rows up to said at least one spare row, and
• (d) using said defective row signal to switch the match line output of said row adjacent said defective row to the match line input of said defective row and switching said subsequent row match line output to said adjacent row match line input, repeating said switching for subsequent match lines up to said match line of said at least one spare row.