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US5734606A
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Multi-piece cell and a MRAM array including the cell
Assignee: Everspin Technologies Inc
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Filing: 1996-12-13
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Granted: 1998-03-31
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Expires: 2016-12-13
Abstract
Abstract New types of memory cell structures (20, 40) for a magnetic random access memory are provided. A memory cell (20, 40) has a plurality of cell pieces (21-24) where digital information is stored. Each cell piece is formed by magnetic layers (27, 28) separated by a conductor layer (29). A word line (25, 41) is placed adjacent each cell piece for winding around cell pieces (21-24) and meandering on a same plane on cell pieces (21-24), for example. The invention attains less power consumption and effective usage for a word current.
Inventors
- 👤 Saied N. Tehrani
- 👤 Eugene Chen
- 👤 Ronald N. Legge
- 👤 Xiaodong T. Zhu
- 👤 Mark Durlam
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 10:35
CPC Classifications
G; G11; G11C; G11C11/00; G11C11/02; G11C11/14; G11C11/15
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
81 words
A magnetic random access memory cell comprising: a plurality of cell pieces, each cell piece having a plurality of magnetic layers separated by a conductor layer; a single word line, placed adjacent each of the cell pieces, for applying a magnetic field created by a word current flowing in the word line to each of the cell pieces; and a sense line, electrically connected to each of the cell pieces in series for sensing a state stored in the memory cell.
Claim 2
Dependent Claim
81 words
A magnetic random access memory cell comprising: a plurality of cell pieces, each cell piece having a plurality of magnetic layers separated by a conductor layer; a single word line, placed adjacent each of the cell pieces, for applying a magnetic field created by a word current flowing in the word line to each of the cell pieces; and a sense line, electrically connected to each of the cell pieces in series for sensing a state stored in the memory cell.
Claim 3
Dependent Claim
29 words
The magnetic random access memory cell of claim 1 wherein the word line is placed adjacent at least one magnetic layer and another magnetic layer of the cell piece.
Claim 4
Dependent Claim
19 words
The magnetic random access memory cell of claim 1 wherein the word line is wound around the cell piece.
Claim 5
Dependent Claim
30 words
The magnetic random access memory cell of claim 1 wherein the word line is formed on a same plane and perpendicularly crossed over the sense line on the cell piece.
Claim 6
Dependent Claim
45 words
The magnetic random access memory cell of claim 1 wherein the cell piece has a relationship of 1<L/W<5, where L is a length of the cell piece along the sense line and W is a width of the cell piece perpendicular to the sense line.
Claim 7
Dependent Claim
32 words
The magnetic random access memory cell of claim 5 wherein each cell piece is placed at least an amount of the width of the cell piece apart from the other cell piece.
Claim 8
Dependent Claim
16 words
The magnetic random access memory cell of claim 1 wherein the magnetic layers have different thicknesses.
Claim 9
Dependent Claim
120 words
A memory array in a magnetic random access memory device comprising: a plurality of memory cells arrayed in rows and columns in a matrix, each memory cell having first to Nth cell pieces, each cell piece having a plurality of magnetic layers separated by a conductor layer; a plurality of word lines, one word line for each column, each word line placed adjacent each of the cell pieces of each memory cell in the column, for applying a magnetic field created by a word current flowing in the word line to the cell pieces; and a plurality of sense lines, each sense line electrically connected to the cell pieces in series for sensing a state stored in the memory cell.
Claim 10
Dependent Claim
120 words
A memory array in a magnetic random access memory device comprising: a plurality of memory cells arrayed in rows and columns in a matrix, each memory cell having first to Nth cell pieces, each cell piece having a plurality of magnetic layers separated by a conductor layer; a plurality of word lines, one word line for each column, each word line placed adjacent each of the cell pieces of each memory cell in the column, for applying a magnetic field created by a word current flowing in the word line to the cell pieces; and a plurality of sense lines, each sense line electrically connected to the cell pieces in series for sensing a state stored in the memory cell.
Claim 11
Dependent Claim
53 words
The memory array of claim 8 wherein the word line is consecutively formed from adjacent the first cell pieces to adjacent the Nth cell pieces in the memory cell placed on the column line, wherein the word line extends above and below each cell piece of each memory cell in the column line.
Claim 12
Dependent Claim
16 words
The memory array of claim 8 wherein the word line is formed on a same plane.
References Cited (Backward Citations)
US5432734A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-03-30 | 2001-09-29 | 2002-03-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-03-30 | 2005-09-29 | 2006-03-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-03-30 | 2009-09-29 | 2010-03-31 | $7700.00 | Window Closed / Lapsed |