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US 2002/0172068 A1Published application
Thin film magnetic memory device having a magnetic tunnel junction
AssigneeMitsubishi Denki Kabushiki Kaisha
InventorHideto Hidaka
Life of this patent
Estimating the term…
Abstract
Bit lines and source lines are precharged to a power supply voltage before data read operation. In the data read operation, a corresponding bit line is coupled to a data bus as well as a corresponding source line is driven to a ground voltage only in the selected memory cell column. In the non-selected memory cell columns, the bit lines and the source lines are retained at the precharge voltage, i.e., the power supply voltage. No charging/discharging current is produced in the bit lines of the non-selected memory cell columns, that is, a charging/discharging current that does not directly contribute the data read operation is not produced, thereby allowing for reduction in power consumption in the data read operation.
Claims26
A thin film magnetic memory device, comprising:
- a plurality of memory cells each having its electric resistance value varying according to a storage data level written thereto by an applied magnetic field;
- a plurality of first data lines respectively provided for fixed groupings of said plurality of memory cells, for reading said storage data level in data read operation;
- a plurality of source lines provided respectively corresponding to said plurality of first data lines, and each electrically coupled to a corresponding one of said plurality of first data lines through a selected one of the memory cells in a corresponding fixed grouping in said data read operation;
- a plurality of first data line selection portions provided respectively corresponding to said plurality of first data lines, each of said plurality of first data line selection portions precharging a corresponding one of said plurality of first data lines to a first voltage before said data read operation, and electrically disconnecting said corresponding first data line from said first voltage in said data read operation;
- and
- a plurality of source line selection portions provided respectively corresponding to said plurality of source lines, each of said plurality of source line selection portions including
- a source line precharging portion for precharging a corresponding one of said plurality of source lines to a second voltage before said data read operation, and
- a source line driving portion for electrically coupling said corresponding source line to a third voltage in said data read operation.
5 more elements
A thin film magnetic memory device, comprising:
- a memory cell for storing data, wherein
- each of said memory cells includes a magnetic storage portion having its electric resistance value varying according to a storage data level, said magnetic storage portion including
- a first magnetic layer retaining a prescribed fixed magnetization direction, and
- a second magnetic layer retaining a magnetization direction written according to combination of a first data write magnetic field for applying a magnetic field in a hard magnetization axis direction and a second data write magnetic field for applying a magnetic field in an easy magnetization axis direction, said thin film magnetic memory device further comprising:
- a first signal line for passing therethrough a first data write current generating said first data write magnetic field;
- and
- a second signal line for passing therethrough a second data write current generating said second data write magnetic field, wherein
- supply of said first data write current is started prior to supply of said second data write current in data write operation.
5 more elements
A thin film magnetic memory device, comprising:
- a plurality of memory cells arranged in a matrix, each of said plurality of memory cells including a magnetic storage portion having its electric resistance value varying according to a storage data level written therein by combination of first and second data write magnetic fields;
- a plurality of write word lines provided respectively corresponding to memory cell rows, and selectively activated in data write operation to pass therethrough a first data write current for generating said first data write magnetic field;
- a plurality of bit lines provided respectively corresponding to memory cell columns;
- a plurality of source lines provided respectively corresponding to said memory cell columns, each of said plurality of source lines interposing the memory cells on a corresponding memory cell column between itself and a corresponding one of said plurality of bit lines;
- a plurality of coupling switches provided respectively corresponding to said memory cell columns, for electrically coupling one of said plurality of source lines and one of said plurality of bit lines to each other at their respective one ends in said data write operation according to a column selection result;
- and
- a data write circuit for supplying a second data write current for generating said second data write magnetic field in said data write operation, said data write circuit coupling, according to said column selection result, one of said plurality of source lines to one of first and second voltages and one of said plurality of bit lines to the other voltage at the other ends according to said storage data level.
4 more elements
A thin film magnetic memory device, comprising:
- a plurality of memory cells arranged in a matrix, each of said plurality of memory cells including a magnetic storage portion having its electric resistance value varying according to a storage data level written by combination of first and second data write magnetic fields;
- a plurality of write word lines provided respectively corresponding to memory cell rows, and selectively activated in data write operation to pass therethrough a first data write current for generating said first data write magnetic field;
- a plurality of source lines provided respectively corresponding to said memory cell rows, and coupled to a first voltage at their respective one ends;
- a plurality of bit lines provided respectively corresponding to memory cell columns, and selectively receiving a second data write current for generating said second data write magnetic field in said data write operation according to a column selection result;
- and
- a word line driver for coupling the activated write word line to a second voltage at its one end in said data write operation, wherein
- said second data write current flows through a current path formed from said activated write word line and at least one of said plurality of source lines which is electrically coupled to said activated write word line at the other ends.
4 more elements
A thin film magnetic memory device, comprising:
- a plurality of memory cells arranged in a matrix, each of said plurality of memory cells including
- a magnetic storage portion having its electric resistance value varying according to a storage data level written therein by combination of first and second data write magnetic fields, and
- an access portion coupled in series with said magnetic storage portion, and selectively turned ON in data read operation to pass a data read current therethrough and turned OFF in data write operation, said thin film magnetic memory device further comprising:
- a plurality of read word lines provided respectively corresponding to memory cell rows, for turning ON said access portion in said data read operation according to a row selection result;
- a plurality of write word lines provided respectively corresponding to said memory cell rows, and selectively activated to pass therethrough a first data write current generating said first data write magnetic field in said data write operation;
- a plurality of bit lines provided respectively corresponding to memory cell columns, each of said plurality of bit lines being electrically coupled to said plurality of write word lines through said memory cells;
- a word line driver for coupling the activated write word line to a first voltage at its one end and setting the remaining write word lines to a second voltage in order to supply a second data write current for generating said second data write magnetic field in said data write operation;
- coupling switches respectively coupled between each write word line and a plurality of write word lines of other memory cell rows, each of the coupling switches being turned ON when one of the two write word lines coupled thereto is activated;
- and
- a data read circuit for supplying said data read current to one of said plurality of bit lines in said data read operation according to a column selection result, and conducting said data read operation based on a voltage change on said bit line corresponding to said column selection result, wherein
- said word line driver sets each of said plurality of write word lines to a prescribed voltage in said data read operation.
8 more elements
A thin film magnetic memory device, comprising:
- a plurality of memory cells arranged in a matrix, each of said plurality of memory cells including
- a magnetic storage portion having its electric resistance value varying according to a storage data level written therein, and
- an access portion selectively turned ON in data read operation to pass a data read current therethrough, said thin film magnetic memory device further comprising:
- a plurality of data lines provided respectively corresponding to memory cell columns, for selectively receiving said data read current in said data read operation;
- and
- a plurality of reference voltage generating portions provided respectively corresponding to said memory cell columns, each of said plurality of reference voltage generating portions being selectively activated in said data read operation according to a column selection result to produce a reference voltage to be compared with a voltage on a corresponding one of said plurality of data lines, wherein
- each of said plurality of memory cells is coupled between a corresponding one of said plurality of data lines and a prescribed voltage.
4 more elements
Dependencies are inferred from the claim text.