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MRAM faster than DRAM?

Discussion in 'Electronic Design' started by Sanny, Mar 15, 2008.

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  1. Sanny

    Sanny Guest

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    DRAM is used in satellites too...
    I have no idea how fast MRAM is but I know for sure that it is way, _way_
    more expensive than both DRAM and Flash.

    - --
    Brendan Gillatt | GPG Key: 0xBF6A0D94
    brendan {a} brendangillatt (dot) co (dot) uk
    http://www.brendangillatt.co.uk
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  3. Nemo

    Nemo Guest

    I read that MRAM is many times faster than DRAM and used in an
    I think the main reason it's used in satellites is that it's rad-hard
    (ie, unlike a normal memory cell, it is much less likely that cosmic
    rays will corrupt its contents).
    I have used it and yes, it's fast, dunno if it's faster than DRAM etc
    though! What the article says is is, it is faster than *Flash* for
    writing. I figured it was essentially as fast as SRAM, but nonvolatile
    (ie, the data stays there when the power goes off).

    MRAM has been for sale for many years under the name FRAM. For info
    about FRAMs look at
    www.ramtron.com
    a small American company who have been making them for over a decade.
    The main problem with their product is that the memories don't come in
    large sizes - they haven't had the financial resources to make (8Mbit?
    Whatever the current Flash sizes are) so they've had to aim for "small,
    specialist, cost-no-object" niches. The sizes are too small for camera
    memories.

    FRAMs have been around a long time and Hitachi, for example, were very
    interested in them a decade ago and promised an imminent release of some
    products. Then one of our periodic semicinductor industry contractions
    occurred and they decided to focus elsewhere (DRAMS I think). Now FRAMS
    are back in fashion - Texas is into them too, I suspect they've licensed
    Ramtron's technology - but they tend to be called MRAMs by other
    companies, I am not sure if there is a subtle difference between MRAM
    and FRAM or if this is simply a marketing ploy.

    What a lot of people want is FRAM built into microcontrollers in place
    of Flash. The first company to market that will clean up a lot of
    applications.
     
  4. davewang202

    davewang202 Guest

    FRAM (or more commonly referred to as FeRAM) is a type of memory
    storage technology that is distinctly different from MRAM. It's not
    marketing.

    MRAM is potentially a better technology than FeRAM, but FeRAM
    technology is far more mature at present.

    http://en.wikipedia.org/wiki/Ferroelectric_RAM
     
  5. Nemo

    Nemo Guest

    FRAM (or more commonly referred to as FeRAM) is a type of memory
    I stand corrected. I see now why I made that error, but it's irrelevant
    to the newsgroup.
    Useful article, thanks.

    I'm not quite clear why you say MRAM is potentially better than FRAM. I
    think the two technologies have similar speeds, and as far as I can see
    there are proven FRAM products out there in the marketplace, but MRAM
    ones are not available yet. From the Wiki articles, *theoretically* it
    looks like MRAM can be denser... but maybe FRAM can too, and it's a
    proven commercial product which is gradually improving.
     
  6. davewang202

    davewang202 Guest

    You'll forgive me as I will tend to be somewhat pedantic about
    correctness of nomenclature and details on memory devices - I taught a
    class on memory systems, and I also co-authored a book on the topic.
    (Doesn't mean that I don't make mistakes of my own of course - plenty
    of those to go around)
    The statement is about the fundamental characteristic of the memory
    storage element - in terms of scalability etc.

    A very concise, accurate, and up-to-date comparison of the various
    memory technologies can be found in the 2007 ITRS roadmap.

    http://www.itrs.net/Links/2007ITRS/2007_Chapters/2007_ERD.pdf
    (page 11)

    MRAM technology senses current - or more accurately magnetic state
    differences in each cell. FeRAM technology senses charge levels on a
    ferrorelectric capacitor. MRAM promises to have much better
    scalability in the long run, more able to utilize advanced feature
    sizes, as stated in the ITRS roadmap.

    OTOH, it takes more energy to do writes into an MRAM cell - even
    papers that proposes to lower MRAM cell write current levels still
    have energy levels that's much larger than existing FeRAM cells.

    David
     
  7. Nemo

    Nemo Guest

    You'll forgive me as I will tend to be somewhat pedantic about
    OK - I've used serial FRAMs (er, FeRAMs) so thought I knew what I was on
    about, but you have out-geeked me 8)

    A pleasure to be corrected by a real authority, and so politely. Thanks.
    I am downloading the PDF you pointed at now to study it further.

    In the kinds of applications I work with (read often, write
    occasionally), a higher write current isn't relevant, so I'd jump at
    MRAM's if they were cost effective.
     
  8. TheM

    TheM Guest

    I like them for their durability. When used with serial interface you can't destroy them
    if your program goes nuts and writes to a location in a loop.
    EEPROM won't survive that for very long.

    Another big plus is that writing takes a lot less time.

    Mark
     
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