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From SRAM to FRAM......advice needed

For a new design I'm thinking of using FRAM instead of the SRAM for data storage in a redesign of one of in our products.

The FRAM looks good in terms of its non-volatility (10 yrs) and is available with serial or parallel interfaces, speed is acceptable - we don't need "fast".

Our products are battery powered and use the main battery & a smaller Li backup battery to retain data in SRAM memory. We'd probably use multiple ICs to achieve 1Mx8bit storage. Our volume is around 300 units per annum.

It worries me a bit that we'd be depending on a single source supply - Ramtron seems to be the only manufacurer, is there a reason why?

Has anyone any experiences / gotchas that I'm not considering?

regards rob.

Reply to
Robb
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They are not the only 'manufacturer' of the technology, but are basically the only people selling the chips. They hold the patents. Toshiba manufacture part using this technology under license, but seem to only sell them in their own equipment. SGS-Thompson, were also manfacturing some of the chips (I have had Ramtron parts, with SGS logos in the plastic), and TI, were also making some of the parts. I suspect the 'single source' behaviour, is down to how their licensing is done. A such then, if the company folded, there are other manufacturers who are making/could make the parts, and given the widespread use of this technology now, an alternative would appear as soon as the legal ownership of the patent cold be resolved.

Best Wishes

Reply to
Roger Hamlett

At work we're using a the Simtek STK17TA8 that looks like an SRAM, but when it loses power it does an "autostore[tm]" using power it saved on a special Vcap (under 100uF) pin. It's also a realtime clock which can be battery or supercap backed.

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Ben Jackson AD7GD

http://www.ben.com/
Reply to
Ben Jackson

The Ramtron parts have worked out very well for us. They are now readily available from catalog distribution for low volume products. The combination of high endurance, non-volatility, and fast write time is not available from any other technology.

Reply to
Gary Reichlinger

I looked up the pdf and it looks just like what I'm looking for. How much are you paying for one (100-200 units ballpark)?

FRAM seems a bit expensive. If STK17TA8 offered RTC at the same price I'd consider it.

SioL

Reply to
SioL

Why? A low-power 8 mbit SRAM is cheap and multisourced, and you already have the lithium backup. I've tested lithiums after as much as

10 years in the field, backing up srams, and the old ones seem to have as many remaining mAh as new ones. Sometimes more!

John

Reply to
John Larkin

Maybe you found another pdf.

Look at the one from Simtek web site, the RTC is built in.

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Reply to
Donald

Sorry, I have no idea.

The part I quoted has an integrated RTC. It also has a watchdog timer.

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Ben Jackson AD7GD

http://www.ben.com/
Reply to
Ben Jackson

I know its got RTC, just wondering whether its in the same price range "while it offers it". Maybe I expressed myself awkwardly.

SioL

Reply to
SioL

A quick google on "what is a FRAM" without quotes turned up Fujitsu:

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And more links - that's the only one I've clicked.

Cheers! Rich

Reply to
Rich Grise

Sometimes our product is flooded or lightning damaged or chewed on by something - hopefully FRAM would make data recovery a little more robust. You are right SRAM is both cheap and multisourced.

Thanks for all the replies guys, I'll check out the suggestions.

regards. r.

Reply to
Robb

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