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US 5,946,227 AGranted
Magnetoresistive random access memory with shared word and digit lines
AssigneeMotorola, Inc.
InventorPeter K. Naji
Life of this patent
Estimating the term…
Abstract
A high speed and high density magnetoresistive random access memory (MRAM) device (30) is provided. The MRAM device employs a poly-silicon word line (39a) that saves wiring space. Further, the word line is connected to a digit line (38a) by a connecting line (44a) which reduces a electrical resistance between transistors (43a) and (40a). Arrangement of the connecting line reduces a transmission time from a digit current control (33a) to transistor (43a) and greatly improves a memory cycle time.
Claims24
A magnetic random access memory unit comprising:
- a memory element including:
- a magnetic memory cell having first and second magnetic layers separated by a non-magnetic layer;
- and
- a memory cell switch being connected in series to the magnetic memory cell for activating the magnetic memory cell;
- a bit line being placed on the first magnetic layer and electrically coupled to the first magnetic layer;
- a digit line being placed adjacent the memory cell, electrically isolated from the memory cell, and perpendicularly placed to the bit lines;
- a word line being placed in parallel to the digit line and coupled to the memory cell switch for controlling the memory cell switch;
- and
- a connecting line for electrically connecting the digit line to the word line.
6 more elements
A magnetic random access memory bank comprising:
- a plurality of memory elements, each memory element including:
- a magnetic memory cell having first and second magnetic layers separated by a non-magnetic layer;
- and
- a memory cell switch being connected in series to the magnetic memory cell for activating the magnetic memory cell;
- a plurality of bit lines, each bit line being placed on the first magnetic layer and electrically coupled to the first magnetic layer;
- a digit line being placed adjacent the memory cell, electrically isolated from the memory cell and perpendicularly placed to the bit lines;
- a word line being placed in parallel to the digit line and coupled to memory cell switches for controlling the memory cell switches;
- and
- a plurality of connecting lines for electrically connecting the digit line to the word line at every N memory elements, wherein the N is a predetermined positive integer number.
6 more elements
A magnetic random access memory device comprising:
- a memory array including a plurality of memory elements arranged in rows and columns, each memory element having:
- a magnetic memory cell including first and second magnetic layers separated by a non-magnetic layer;
- and
- a memory cell switch being connected in series to the magnetic memory cell for activating the magnetic memory cell;
- a plurality of bit lines, each bit line being placed on first magnetic layers of magnetic memory cells arranged in a column line and electrically coupled to the first magnetic layers;
- a plurality of sets of digit and word lines, each set of digit and word lines having:
- a digit line being placed adjacent memory cells arranged in a row line, electrically isolated from the memory cells, and perpendicularly placed to the plurality of bit lines;
- and
- a word line being placed in parallel with the digit line and coupled to memory cell switches arranged in the row line for controlling the memory cell switches;
- a plurality of sets of connecting lines, each set of connecting lines for electrically connecting between the digit line and the word line at every N memory elements in the row line, wherein the N is a predetermined positive integer number;
- a bit line controller, coupled to the plurality of bit lines, for selecting one of the plurality of bit lines;
- and
- a digit line controller, coupled to the plurality of digit lines, for selecting one of the plurality of digit lines.
10 more elements
Dependencies are inferred from the claim text.