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US 2004/0105304 A1Published application
Thin film magnetic memory device with memory cells including a tunnel magnetic resistive element
AssigneeMitsubishi Denki Kabushiki Kaisha
InventorHideto Hidaka
Life of this patent
Estimating the term…
Abstract
A data bus is precharged to a precharge voltage before data read operation. In the data read operation, the data bus thus precharged is electrically coupled to the same voltage as the precharge voltage through a selected memory cell. A driving transistor couples the data bus to a power supply voltage (driving voltage) in order to supply a sense current in the data read operation. A charge transfer amplifier portion produces an output voltage according to an integral value of the sense current (data read current) flowing through the data bus, while maintaining the data bus at the precharge voltage. A transfer gate, differential amplifier and latch circuit produce read data based on the output voltage sensed at prescribed timing.
Claims15
A thin film magnetic memory device, comprising:
- a plurality of magnetic memory cells each having its electric resistance value varying according to a storage data level written therein by an applied magnetic field;
- a first data line electrically coupled to a first voltage through a selected one of said plurality of magnetic memory cells in data read operation;
- a first precharging circuit for setting said first data line to a precharge voltage before said data read operation;
- a first read driving circuit for supplying a data read current to said first data line in said data read operation;
- a first charge transfer feedback amplifier portion provided between said first data line and a first internal node, for retaining a voltage on said first data line and producing a first output voltage onto said first internal node according to an integral value of said data read current flowing through said first data line;
- and
- an amplifier portion for producing read data based on the voltage on said first internal node.
4 more elements
A thin film magnetic memory device, comprising:
- a plurality of magnetic memory cells for storing data written by an applied magnetic field, each of said plurality of magnetic memory cells including
- a magnetic storage portion having one of a first electric resistance value and a second electric resistance value that is larger than said first electric resistance value, according to a level of said storage data, and
- a memory cell selection gate connected in series with said magnetic storage portion, and rendered conductive when selected;
- a first data line electrically coupled to said magnetic storage portion and said conductive memory cell selection gate of a selected magnetic memory cell and receiving a data read current in data read operation;
- a dummy memory cell having an intermediate electric resistance value of said first and second electric resistance values, said dummy memory cell including
- a dummy resistance portion having said first electric resistance value, and
- a dummy memory cell selection gate connected in series with said dummy resistance portion, and rendered conductive when selected;
- a second data line electrically coupled to said dummy resistance portion and said conductive dummy memory cell selection gate and receiving said data read current in said data read operation;
- and
- a data read circuit for producing read data based on a voltage change on said first and second data lines, wherein
- an electric resistance value of said conductive dummy memory cell selection gate is larger than a third electric resistance value and is smaller than a sum of a difference between said second and first electric resistance values and said third electric resistance value, said third electric resistance value being an electric resistance value of said conductive memory cell selection gate.
8 more elements
A thin film magnetic memory device, comprising:
- a plurality of magnetic memory cells for storing data written by an applied magnetic field;
- a dummy memory cell for comparison with a selected one of said plurality of magnetic memory cells in data read operation, each of said magnetic memory cells and said dummy memory cell including
- a magnetic storage portion having one of a first electric resistance value and a second electric resistance value that is larger than said first electric resistance value, according to a level of said storage data, and
- a memory cell selection gate connected in series with said magnetic storage portion, and rendered conductive when selected, said magnetic storage portion included in said dummy memory cell storing data at a level corresponding to said first electric resistance value;
- a first data line electrically coupled to one of said selected magnetic memory cell and said dummy memory cell in said data read operation;
- a second data line electrically coupled to the other of said selected magnetic memory cell and said dummy memory cell in said data read operation;
- a data read circuit for supplying a data read current to each of said first and second data lines and producing read data based on a voltage change on said first and second data lines in said data read operation;
- and
- a dummy resistance adding circuit for selectively connecting a resistance portion in series with one of said first and second data lines that is electrically coupled to said dummy memory cell, said resistance portion having an electric resistance value smaller than a difference between said first and second electric resistance values.
6 more elements
Dependencies are inferred from the claim text.