Flash Ram - How long does it last?

Jun 27, 2006 7 Replies

How long can you expect programs, burnt into the flash ram of microprocessor chips, to last? If I make up a piece of equipment based on say, an ATMEL AT90S2313 chip how long could this stay in service before getting "soft" bits? Thanks.



Here is the Flash reliability report for that device:

formatting link
As you can see, zero failures for the samples, so they can only guess the typical retention rate.

But in practice you are talking a decade or two at the least for typical use in modern Flash micros. But if you are a pessimist...

What is your product service life?

Dave :)

Actually, there is more chance the particular device will have gone obsolete before the the Flash memory gives up the ghost. The AT90S2313 is already obsolete and not recommended for new designs.

It can be a real bugger getting an obsolescence guarantee out of manufacturers, let alone a guarantee on Flash retention.

Dave :)

Flash technology can be very different between microcontrollers. I had a few AT89C51 devices running in an environment between 5 degrees and 65 degrees. They lasted about 18 months before the flash started to show errors.

These devices have 1994 date codes, so the technology may have been quite early in the microcontrollers.

I'm using the PIC micros now and the current ones have lasted for over 5 years in the same environment (still running).

Yes, Flash technology in general wasn't that great a decade or more back, the technology wasn't very mature. Leakages were high and not very well controlled.

The PICs have always had a better rep than the Atmels in this regard, but I suspect they are pretty even these days.

Dave :)

I have a product I designed in 1986 with the MC68705P3 and R3 variants, these still sometimes come back for warranty service, usually transformers and external connections suffer due to excessive vibration. The firmware in the processor has integrity check and hasnt once reported any error in that time for any of the almost 100 units in the field, however it is a UV eprom type with larger cells than probably all flash rom today.

Guarantees on anything are getting more difficult as that then implies a consequential damages issue

Regards Mike * GMC/VL Commodore, Calais VL Turbo FuseRail that wont warp or melt ! * High grade milspec ignition driver electronics now in development * Twin Tyres to suit most sedans, trikes and motorcycle sidecars http://niche.iinet.net.au

If it's a AT90s2313 there's 100% probability of that, it's obsolete already.

The ATTiny2313 should be available for a while though, and is AFAIK pin-compatible.

Bye. Jasen

I have a pic16f876 on a design i did about 5 year ago. There was about

10k made and they are all still going strong. A few failures, but none related to the actual micro.

Join the Discussion

Have something to add? Share your thoughts — no account required.

Didn't find your answer?

Ask the community — no account required