Patent ID: 6922355

Claim:
A thin film magnetic memory device, comprising: a plurality of memory cells for storing data, wherein each of said memory cells includes an access gate selectively turned ON in data read operation, and a magnetic storage portion connected in series with said access gate, and having either a first electric resistance or a second electric resistance higher than said first electric resistance depending on the stored data, and said thin film magnetic memory device further comprising: a data line that is electrically coupled to a selected memory cell through a turned-ON access gate of said selected memory cell in said data read operation, said selected memory cell being a memory cell selected from said plurality of memory cells for said data read operation; a reference data line for transmitting in said data read operation a read reference voltage for comparison with a voltage on said data line; and a plurality of dummy memory cells for producing said read reference voltage, wherein each of said dummy memory cells includes a dummy access gate selectively turned ON in said data read operation, and a plurality of dummy magnetic storage portions are electrically coupled to said reference data line in response to turning-ON of said dummy access gate, and each having either said first electric resistance or said second electric resistance depending on data written therein, each of said dummy magnetic storage portions is connected in series with at least another one of the plurality of dummy magnetic storage portions.