| 摘要 |
PROBLEM TO BE SOLVED: To reduce power consumption of a MRAM device formed of magnetic memory cells having magnetic tunnel junctions. SOLUTION: Each of bit lines BL and source lines SL is pre-charged to power source voltage VDD before read-out of data. At the time of read-out of data, only in a selected memory cell column, a corresponding source line SL is coupled to a data bus line DB, while a corresponding source line is driven to ground voltage VSS. In non-selection memory cell columns, each of bit lines BL and source lines SL is kept at the power source voltage VDD. As a charge/ discharge current is not caused in bit lines BL corresponding to the non-selection memory cell columns which does not contribute directly to read-out of data, power consumption at the time of read-out of data can be reduced.
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