Is it safe to use old but packed ICs

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Hi Guys,

A little offbeat question.

Is it safe to use Old Ics - say 10-15 yrs old - but still in proper company packing?

Or

What is the expiry of an unused IC?

Need to make an procurement. But the IC packing says its 12 yrs old. Can I buy it? I can't buy the newer equivalents because of the price constraint.

Thanks

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Why not? They are not made with food.

Ross McKenzie ValuSoft Melbourne Australia

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The only things to be wary of that I can think of:

1) Ensure if it's old silicon there is no errata that would be a show-stopper for your project or product

2) Ensure the chips are appropriately sealed - if they are moisture sensitive for example, make sure the manufacturer packaging is still air-tight

3) Make sure they have appropriate tools support if they require programming (FPGAs, Microcontrollers, etc.) so that you aren't stuck trying to dig up a PC and software that is a decade old

- Dean :twisted:

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I'd say it depends.

If you need to fullfill some environmental standards, it is most likely that components such old do not conform to modern environmental standards.

Also old components tend to gather some oxidation to their IO pins, the main reason any component has an expiration date is that they do not solder so well any more and connection might be unreliable.

If you are just making these devices for yourself, all this may not be a problem.

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valusoft wrote:
Why not? They are not made with food.

that is not true....
Food is made out of carbons and so are the IC's
even worst some people like to eat sand( there is a dutch saying that sand sands the stomach) and definitely ICs are made out of sand.

but serious, if you use the chips and they have been packaged all the time you should be OK. But be ware that then the package should contain an indicator on if the ICs have been humid or not.
Best thing is to bake them before using,specially when in production.
Any humidity that got in the package will make the chip explode in the reflow oven if you do not do this.

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Thanks guys.

Programming, Errata & environmental stds are not applicable to my project.
Actually its a one-off project for a marketing firm which includes LMC555CM of National Semiconductors (then).

Humidity aspect & packaging I will definitely check. I tried a few samples though. They worked alright.

Hope there should be nothing more to look for.

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if it is only for a one off that you will solder by hand, there will be no humidity issues(assuming to assembly by hand and do not use a reflow oven.

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No actually I am outsourcing it for Wave Soldering. Its about 10k pcs, hence the concern :)

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It should be OK. It's called New-Old-Stock - ebay's full of it. Silicon should have a very long shelf life.

The pins should be OK if they are standard coated. But beware of certain materials - silver is an exotic, but not unheard of coating material for throughhole parts. The same goes for anything that might oxidize. I suggest that you buy one part and see how the soldering goes.

There are pointy haired bald people.
Time flies when you have a bad prescaler selected.

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Thanx daqq. Its SMD. I tried 4-5 parts. They soldered just fine.

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For 10k units you're putting your balls on the line. What happens if the chips start dying 6 months after you've shipped the boards? The saving will quickly evaporate and there's no warranty fallback from the supplier. I'd say you're taking a gamble.

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I'd agree with Kartman. If you do go ahead though, make sure that the device are baked before soldering otherwise you may dmage them due to moisture. This applies whether the parts are new or old. With parts this old, even if they are still sealed they will need baking as moisture barriers are only rated for months, not years.

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Kartman you are scaring me now :)

Product life is 45 days but 24 hrs. Runs on AA batteries.

The problem is the sample got approved but I fell short of 10k stock - classical problem I guess. But I am learning.

And the newer substitutes will leave me in loss. So I am kinda fixed here.

Need to take calculated risk. I will definitely bake them before use.

Anymore parameters to consider?

Thanx for all the help!

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Jepael wrote:
I'd say it depends.

If you need to fullfill some environmental standards, it is most likely that components such old do not conform to modern environmental standards.

Also old components tend to gather some oxidation to their IO pins, the main reason any component has an expiration date is that they do not solder so well any more and connection might be unreliable.

If you are just making these devices for yourself, all this may not be a problem.


Old components tend to gather some oxidation to their IO pins: true, but I can still solder old stuff of 35 years ago.
What is REALLY going to be a problem (hmm, it already is ....) : the ROHS crap. Pin-headers I bought a few years back: a freaking pain to get those soldered. Same for IC sockets. These days I search a bit longer in the old-stuff-boxes to find a pre-ROHS version of components. In a year or so I may have to dump most of the smd components :(

To OP: very good recommendations so far. So: it WAS a lucky shot, now it's an educated guess :)

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One more thing.

Obviously I am going to test the xircuit.

Since the main issue looks like getting it right the first time - soldering process, So once it is tested, probability of failure in next 45 days should be very less, right?
.

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kpanchamia wrote:
So once it is tested, probability of failure in next 45 days should be very less, right?
.
:lol: except for those that actually fail. (probability: a branch of statistics which attempts to predict the likelihood of some event... like success or failure)

Ross McKenzie ValuSoft Melbourne Australia