[General] IC / PIC / AVR / ARM storage outside room/garage question

[Garyl]

Hello all,
Can anyone tell me what are the safe DIP or maybe SMD IC storage requirements, mostly for MICROCONTROLLERS?
I live in central europe and I am thinking about setting up a little amateur electronic workshop in the garden in some kind of barn, but the temperature here at winter reaches -5C, maybe -10C at worst cases, and it reaches 30C or so at the summer.
Could such temperature (-10C to 35C or so) damage the ICs, or do I just need to store them somehow?
What about humidity etc?
Do I really need constant room temperature for storing ICs?

 

[esp1]

hi,
Most IC's are rated as -60C thru +150C for storage limits.

Humidity can cause some tarnishing of the pins, so keep them stored in anti-electrostatic bags.

Wear a wrist earthing band when handling IC's, to avoid ESD damage.

I have had IC's stored in out buildings for many years using these storage conditions.

E

 

[andre_luis]

Prolonged exposition to extreme and broad variation of temperatures is always an unwanted condition in the sense of degrading the integrity of the component within the parameters for which it was specified, but in any case, the temperatures range mentioned above does not seem so aggressive at all for storage purpose. In that case, the impact would only be within the component. For the humidity however, the damage occurs at the pins whenever condensation occurs, what means, when temperature reaches the zero above. If I were you I would take special care with the SMD which for some reason ( perhaps a thinner finishing ) get their pins rusty more easily.

 

[FvM]

Humidity can cause some tarnishing of the pins, so keep them stored in anti-electrostatic bags.

Only effective if the bags are sealed and some amount of desiccant put inside, as with factory or distributor packed devices.

Besides tarnishing of pin surfaces, the major risk is package delamination during reflow solder caused by humidity absorbed in the package material. ICs must be either stored in dry atmosphere or baked before assembly according to manufacturer specification.

 

[Garyl]

How do I "bake" ICs in amateur home conditions?

What if I store only the DIP package ICs outside - in the antistatic bags - will it be enough or do I have to take some more precautions?

 

[Garyl]

I have some DIP or even TQFP ICs that are orignally packed by manufacturrer, like AVRs and PICs, and they do not have desiccant inside.
Why is that so?
So, do I have to open those IC bags and put the desiccant inside?

 

[FvM]

Baking conditions are specified by manufacturers. It's well possible in an electric baking oven at home.

Again, antistatic bags without desiccant are useless.

- - - Updated - - -

I presume, the original packaging is inert gas filled and sealed which should be O.K. Most manufacturers however have small desiccant bags and humidity indicator tags inside the packaging.

 

[KlausST]

Hi,

storing at cold temperature (within specified storage temperature range) is better than warm temperature.
* slowed migration
* slowed oxidation
* usually less absolute humidity

Bags:
* use ESD bags
* the best is: inert ags filled - then non evacuated with desiccant - then vaccumated with desiccant - then packed without desiccant
(vaccum just needs less space, but with time it generates an atmosphere with a lot of unwanted "ingrediants" like humidity, oxygen and especially plasticizer)

Baking:
* ... avoids problems with humidity in plastics. But it speeds up migration. I don´t recommend to bake them several times.

***
What may happen:
most probably: soldering errors.
With one device (SMD 1206 resistor) I had "invisible" soldering errors (bought from unreliable distributor): Very good, shiny solder surface, good meniscus across the whole PCB pad and device... but it caused isolation after 2 years of operation. One could easily lift off the resistor from the PCB. About no mechanical connection. Hundreds of PCBs with the same error from the same resistor batch.

Klaus

 

[Garyl]

[MERGED] Storing PICs/AVRs with bag and enclosure or just with enclosure

Hey all
The ICs I buy usually ship inside such plastic transparent enclosure:

and those plastic enclosures are inside the anti-static bag:


At my homeI have a plastic drawers, where I store my ICs... and here is my question:
Can I safetely remove the anti static bags and store the DIP / SOIC package ICs just inside that plastic enclosures (first picture)?
I mean, the anti static bags are taking the 80% of space in my drawers and I'm not sure if they are worth it...

Those DIP/SOIC ICs would be stored in those drawers at room temperature for a long time...
How do you guys store your ICs?