Static Bags and Standards

I'm not sure I understand your "complaint." Much of the pink stuff

(And the description of those bags points to a MIL spec that might help answer your larger question.)

The folks that trained me were pretty adamant that the pink stuff would prevent static from building up, but that only the metallized stuff would protect a board inside from Evil Electric Forces (keep in mind that these were trained -- trainers, not EEs).

Pink bags were to be used for non-static sensitive things used around static sensitive things. Metalized (or the heavy black conductive stuff) bags were to be used any time a static-sensitive thing was to be taken out of a static-safe area.

On a well designed board there should not be any extreme ESD sensitivity. Only on loose electronic parts and mainly semiconductors should that be an issue. I've seen pink bags used a lot for boards and modules and the ones I have here are antistatic.

For example, Linear Technology shipped their LT3757 demo kit to me in a pink bag and those guys should really know.

Ob. eevblog reference in which the intrepid Dave has fun with assorted ESD protective material. Shorter version: use the metalized bags.

That must have been in another century :-)

Although I've always wondered why it had to be this ugly pink and couldn't be a more decent color.

The company at the time did seem to be going overboard -- I think to some extent it was because they had this attitude that everyone in production was a dimwit, so you had to overdo the rules in hopes that what you really needed would be adhered to. (We had some really bright folks in production)

They could never accept the assertion that having an EE degree automatically meant that you couldn't be a source of static problems...

One standard is MIL-PRF-81705E (Type I or III): Under 4.6.10 the material should be Inner: Greater than or equal to 1x10^5 ohms/sq but less than 1x10^12 ohms/sq. Outer: less than 1x10^12 ohms/sq This sorta describes the multitude of applicable materials: Anti-static is 10^9 thru 10^12 ohms/sq Static Dissipative is 10^6 through 10^9 ohms/sq Conductive is 10^3 thru 10^6 The pink bags are polyethylene and are considered anti-static.

Also: EIA-541. The definitions are quite different in EIA-541: Conductive less than 10^4 ohms/square Dissipative 10^4 to 10^11 ohms/sqare

The color doesn't mean much in terms of resistivity. Some bags are just conductive on the surface, while others have flake graphite or granular carbon mixed into the poly material. Resistivity also varies somewhat with thickness. As I understand it, unprotected components get static dissipative, while just about everything else can use either anti-static or static dissipative depending on one's level of paranoia. Individual semiconductors sometime get conductive bags.

Ancient horror story: We were shipping finished boards to a customer. Shipping had recently installed a new "chute" type system for easy packing. The chute and ramps were covered with some kind of sheet rubber similar to stair tread protectors. The boards were packet in padded anti-static bags and were launched down the chutes and ramps to the waiting packing boxes. About 1/4 of the boards were dead on arrival. I was working on the problem late at night when someone accidentally turned off the lights. That's when I saw sparks flying all over the bags when they skidded down the ramp. Some of the arcs looked big enough to go right through the padded anti-static bags. I called the bag vendor to practice my profanity. He indicated that the bags will protect against static electricity accumulation, but will not protect against a static discharge which with sufficient voltage can arc right through the bag. Oops.

Some bags also make tolerable Hi-V capacitors:

Pretty much my take. (We also had some real losers)

No, but we did convince them that we weren't operating on customer shippable equipment so latent defects weren't an issue. They still insisted on the whole regalia when we walked on the production floor (including the ill-fitting lab coats).

Green bags: They're biodegradable. Next version might even be edible. Yummmm.

AFAIK i am the only idiot that uses the pink Uline 2 Mil Anti-Static Poly Bags for product.

That's an excellent idea. 25 years ago National had these post-consumer distribution boxes in Germany. Instead of throwing them into the recycling bin you could rip open a bag of seeds (provided by National Semiconductor!), sprinkle, soak the whole thing, and place it in the kitchen window. I did, and a short time later I had fresh cilantro growing in some sort of puffy cardboard.

Next version might even be edible. Yummmm.

Soylent Green? :-)

Why do they make bags that are black plastic inside (I measured about 10M with test leads 1" apart) and pink plastic outside (I couldn't measure the resistance?

Also if the pink plastic didn't protect well enough, why does Dallas use it to ship its clock chips and recommend against the use of metallic bags (drains the internal battery)?

Nice. I lived in a house that had WWII vintage "vegetable board" for wallboard instead of drywall. In the kitchen, above the tea pot, the seeds would sprout and we had zuccini growing out of the wall.

I received a shipment of edible packing material. Of course, I had to try eating it. It was totally tasteless, much like raw tofu or stale popcorn. Made from grain sorghum or corn starch. I couldn't tell which.

I've always wondered what Lincoln was thinking at Gettysburg: ...of the people, by the people, for the people. Kinda sounds like Soylent Green.

Easy. See MIL-PRF-81705E (Type I or III): Under 4.6.10 the material should be Inner: Greater than or equal to 1x10^5 ohms/sq but less than 1x10^12 ohms/sq. Outer: less than 1x10^12 ohms/sq Note that the spec for the inner and outer bag material is different.

Dunno. Maybe pink is good enough.

I use IEC 61340-5-1 "Protection of electronic devices from electrostatic phenomena - general requirements".

After implementing that we changed to pink bags.

Naturally, this is one of those "depends" responses, but *I* always looked at it like this : If the device isn't going to live through the shipping from the assembler to me, it certainly isn't going to survive in the field. None of my customer operate ANY equipment in a static controlled environment. Hell, I'd be happy if their building has any type of functional Earth Ground.

Jim

:-)

Some of my stuff is installed in places where the power and telco grids look like this:

test leads 1" apart) and pink plastic outside (I couldn't measure the resistance?

ship its clock chips and recommend against the use of metallic bags (drains the internal battery)? AFAIK nobody makes that combination. Variations available: pink plastic, uniform outside metallization, uniform inside metallization, "cross-hatch" metallization (i think inside), and uniform outside metallization with thin plastic insulating coating.

• Dallas seems to be in the same non-production boat as Maxim; so does it matter what their vaporware "is shipped" in if it does not (for all practical production purposes) exist?

No static there. Plus with all that metal here and there it's pretty well shielded :-)