Patent ID: 6876576

Claim:
A thin film magnetic memory device, comprising: a plurality of memory cells arranged in rows and columns, each having an electric resistance in accordance with magnetically written data; a plurality of dummy memory cells each having the same electric resistance characteristic as each said memory cell and having data of a prescribed level written in advance therein, each said dummy memory cell being arranged to share one of said rows and columns with said plurality of memory cells and to form the other of said rows and columns; a resistance adjusting portion for electrically coupling a prescribed electric resistance to at least one of the memory cell and the dummy memory cell; a data read circuit performing data read based on a difference between combined resistance of selected one of said plurality of memory cells and said resistance adjusting portion and combined resistance of one of said plurality of dummy memory cells and said resistance adjusting portion; and a redundant unit for replacement of a defective memory cell in said plurality of memory cells and said plurality of dummy memory cells in a unit of said the other of said row and column, said redundant unit including a plurality of spare memory cells arranged in said the other of said rows and columns to share said one of said rows and columns with said plurality of memory cells and said plurality of dummy memory cells, and each said spare memory cell having the same electric resistance characteristic as each said memory cell.