Flash Ram - How long does it last?

[JohnS]

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.

 

[David L. Jones]

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:
http://www.atmel.com/dyn/resources/prod_documents/90S2313.PDF
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

 

[David L. Jones]

Here is the Flash reliability report for that device:
http://www.atmel.com/dyn/resources/prod_documents/90S2313.PDF
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

 

[swanny]

Here is the Flash reliability report for that device:
http://www.atmel.com/dyn/resources/prod_documents/90S2313.PDF
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

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).

 

[David L. Jones]

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.

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.

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

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

Dave

 

[Mike]

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.

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.

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

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

--
Regards
Mike
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http://niche.iinet.net.au

 

[The Real Andy]

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 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.