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US5852574A
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High density magnetoresistive random access memory device and operating method thereof
Assignee: Everspin Technologies Inc
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Filing: 1997-12-24
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Granted: 1998-12-22
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Expires: 2017-12-24
Abstract
Abstract A high density magnetoresistive random access memory (MRAM) device is provided. The MRAM device includes a plurality of magnetic memory cells which employ a giant magnetoresistive effect to read and write states. The magnetic memory cells are divided into groups as memory units. The memory unit is activated by row and column signals provided by row and column decodes, respectively. Then, sense and word currents is applied to a target magnetic memory cell.
Inventors
- 👤 Peter K. Naji
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 20:41
CPC Classifications
G; G11; G11C; G11C11/00; G11C11/02; G11C11/14; G11C11/15
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
85 words
A magnetoresistive random access memory module comprising: memory units being arranged in rows and columns, each of the memory units having a plurality of magnetic memory cells; a plurality of row lines, each row line being coupled to memory units lined in the row; a plurality of column lines, each column line being coupled to memory units lined in the column; and a plurality of second switches, each second switch being coupled to the row line to activate the memory units lined in the row.
Claim 2
Dependent Claim
85 words
A magnetoresistive random access memory module comprising: memory units being arranged in rows and columns, each of the memory units having a plurality of magnetic memory cells; a plurality of row lines, each row line being coupled to memory units lined in the row; a plurality of column lines, each column line being coupled to memory units lined in the column; and a plurality of second switches, each second switch being coupled to the row line to activate the memory units lined in the row.
Claim 3
Dependent Claim
40 words
The magnetoresistive random access memory module as claimed in claim 1 further including a plurality of word lines and a plurality of sense lines, the magnetic memory cells being arranged on intersections of the word lines and the sense lines.
Claim 4
Dependent Claim
85 words
The magnetoresistive random access memory module as claimed in claim 2 further including: a first decoder for providing a row signal on the row line, the row signal activating memory units lined in the row; and a second decoder for providing a word current on the word line and a column signal on the column line, the column signal activating memory units lined in the column and the word line activating the memory cell in the memory unit selected by the row and column signals.
Claim 5
Dependent Claim
23 words
The magnetoresistive random access memory module as claimed in claim 1 wherein the plurality of magnetic memory cells are coupled to in series.
Claim 6
Dependent Claim
32 words
The magnetoresistive random access memory module as claimed in claim 1 wherein the memory unit further includes a first switch coupled to the column and row lines to activate the memory unit.
Claim 7
Dependent Claim
28 words
The magnetoresistive random access memory module as claimed in claim 5 wherein the first switch is coupled to the magnetic memory cells in the memory unit in series.
Claim 8
Dependent Claim
23 words
The magnetoresistive random access memory module as claimed in claim 1 wherein the magnetic memory cell includes magnetic layers separated by non-magnetic layer.
Claim 9
Dependent Claim
96 words
A magnetoresistive random access memory module comprising: memory units being arranged in rows and columns, each of the memory units having a plurality of magnetic memory cells; a plurality of row lines, each row line being coupled to memory units lined in the row; a plurality of column lines, each column line being coupled to memory units lined in the column; and a plurality of second switches that are grouped by groups of second switches, each second switch being coupled to the row line, and each group of second switches being coupled to a control line.
Claim 10
Dependent Claim
96 words
A magnetoresistive random access memory module comprising: memory units being arranged in rows and columns, each of the memory units having a plurality of magnetic memory cells; a plurality of row lines, each row line being coupled to memory units lined in the row; a plurality of column lines, each column line being coupled to memory units lined in the column; and a plurality of second switches that are grouped by groups of second switches, each second switch being coupled to the row line, and each group of second switches being coupled to a control line.
Claim 11
Dependent Claim
40 words
The magnetoresistive random access memory module as claimed in claim 8 further including a plurality of word lines and a plurality of sense lines, the magnetic memory cells being arranged on intersections of the word lines and the sense lines.
Claim 12
Dependent Claim
98 words
The magnetoresistive random access memory module as claimed in claim 9 further including: a first decoder for providing the control signal on the control line, each control signal providing row signals on the group of row lines and activating memory units coupled to the group of row lines; and a second decoder for providing a word current on the word line and a column signal on the column line, the column signal activating memory units lined in the column and the word line activating the memory cell in the memory unit selected by the row and column signals.
Claim 13
Dependent Claim
23 words
The magnetoresistive random access memory module as claimed in claim 8 wherein the plurality of magnetic memory cells are coupled to in series.
Claim 14
Dependent Claim
32 words
The magnetoresistive random access memory module as claimed in claim 8 wherein the memory unit further includes a first switch coupled to the column and row lines to activate the memory unit.
Claim 15
Dependent Claim
28 words
The magnetoresistive random access memory module as claimed in claim 12 wherein the first switch is coupled to the magnetic memory cells in the memory unit in series.
Claim 16
Dependent Claim
23 words
The magnetoresistive random access memory module as claimed in claim 8 wherein the magnetic memory cell includes magnetic layers separated by non-magnetic layer.
Claim 17
Dependent Claim
67 words
A magnetoresistive random access memory device comprising: at least a pair of memory modules, each module having memory units being arranged in rows and columns, and each memory unit having a plurality of magnetic memory cells; a decoder for activating the magnetic memory cell; a detector for sensing states contained in the magnetic memory cell; and an equalizer for adjusting the sense lines at a predetermined voltage.
Claim 18
Dependent Claim
67 words
A magnetoresistive random access memory device comprising: at least a pair of memory modules, each module having memory units being arranged in rows and columns, and each memory unit having a plurality of magnetic memory cells; a decoder for activating the magnetic memory cell; a detector for sensing states contained in the magnetic memory cell; and an equalizer for adjusting the sense lines at a predetermined voltage.
Claim 19
Dependent Claim
53 words
The magnetoresistive random access memory device as claimed in claim 15 wherein the decoder includes a first decoder and a second decoder, the first decoder activating the memory units lined in the row and the second decoder activating the memory units lined in the column and magnetic memory cells in the memory unit.
Claim 20
Dependent Claim
58 words
The magnetoresistive random access memory device as claimed in claim 15 wherein the detector compares an output from a target memory cell in one memory module of the pair of memory modules to an output from a reference memory cell in the other memory module of the pair of memory modules, both cells being activated by the decoder.
Claim 21
Dependent Claim
22 words
The magnetoresistive random access memory device as claimed in claim 15 wherein the equalizer sets a same voltage on the sense lines.
Claim 22
Dependent Claim
23 words
The magnetoresistive random access memory device as claimed in claim 15 wherein the plurality of magnetic memory cells are coupled to in series.
Claim 23
Dependent Claim
23 words
The magnetoresistive random access memory device as claimed in claim 15 wherein the magnetic memory cell includes magnetic layers separated by non-magnetic layer.
Claim 24
Dependent Claim
76 words
An operating method for a magnetoresistive random access memory device having memory units being arranged in rows and columns, each of the memory units having a plurality of magnetic memory cells, the method comprising the steps of: activating the memory unit; activating the magnetic memory cell in the memory unit; applying a sense current to the magnetic memory cell; and equalizing an output from the magnetic memory cell before sensing states in the magnetic memory cell.
Claim 25
Dependent Claim
76 words
An operating method for a magnetoresistive random access memory device having memory units being arranged in rows and columns, each of the memory units having a plurality of magnetic memory cells, the method comprising the steps of: activating the memory unit; activating the magnetic memory cell in the memory unit; applying a sense current to the magnetic memory cell; and equalizing an output from the magnetic memory cell before sensing states in the magnetic memory cell.
Claim 26
Dependent Claim
44 words
The operating method for the magnetoresistive random access memory device as claimed in claim 21 wherein the step of activating the memory unit includes the steps of: activating the memory units lined in the row; and activating the memory units lined in the column.
Claim 27
Dependent Claim
51 words
The operating method for the magnetoresistive random access memory device as claimed in claim 21 wherein the step of activating the magnetic memory cell in the memory unit includes a step of providing a word current and applying a magnetic field created by the word current to the magnetic memory cell.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-12-21 | 2002-06-22 | 2002-12-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-12-21 | 2006-06-22 | 2006-12-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-12-21 | 2010-06-22 | 2010-12-22 | $7700.00 | Window Closed / Lapsed |