ESD protection

[Harry Bissell]

I agree with Rob...

I said I do NOT take special precautions... but I do handle the IC's carefully.
I don't
remove them from the conductive foam or tube until I am ready to plug them in.
I use
sockets so soldering stress is not an issue. If I walk with them, I take care
to hold them
in my hand with all pins touching my skin, and my hand closed around them
(faraday cage effect).

BTW:  The humidity issue is a double edged sword. I have MANY failures in the
field
(think 'firestone') that (thank God) are not life threatening... but they trash
machines !!!
These were traced to some lots of optocouplers made in a plant in Malasia...
and caused
by humidity.  The analysis proved humidity damage... but these units are run in
northern
North America where high humidity is not common.  How did it get into the
(supposed)
sealed package ???   At Manufacture.  Probably started the line with climate
control broken, not installed yet, whatever.  Every one that fails costs anout
$5K in capitial equipment failure, plus lost production....

I think the number of failures in the DIY field due to static is pretty low.
Most of us are
not using really sensitive chips. CMOS is MUCH better than it used to be.
Bipolar is pretty rugged stuff... but at least use common sense in handling
them.

A LOT of damage is caused by faulty design. I'm in the industrial marketplace.
NO CMOS input ever leaves a PCB without some protective components, such as
large value
series resistance, diode clamps, caps, shunt resistance, etc.  MANY boards that
die an early ESD death do not have this protection designed in, and are an
"event" waiting to happen.

IMHO

H^) harry

Rob wrote:

> About 90 percent of non-mechanical after-sale failures can be attributed to
> ESD stresses. The statistics tell the full story.
> You especially see products from developmental countries/economies having
> HUGE reliability issues because they do not want to spend money on ESD
> protection when they first start up and concentrate on production numbers
> too much.
>
> Mainland Chinese corporations still haven't all seemed to have figured it
> out yet.
>
> The marketing ppl keep saying "Why were their products so reliable with the
> first set of samples and the second set are terrible?"
>
> I say "check the weather in the area on that day: first samples were built
> while it was very humid".
>
> Sure enough.  ; )
>
> Sometimes though, I want to just wring ppls necks when they reach for
> something without at LEAST touching first the surface upon which it lies,
> THEN touch the IC or populated board. That simple act alone can save most
> modern ICs.
>
> Rob
>
> ----- Original Message -----
> From: John E Blacet <blacet at monitor.net>
> To: <synth-diy at node12b53.a2000.nl>
> Sent: Saturday, September 09, 2000 8:50 AM
> Subject: Re: ESD protection
>
> > The electronics industry spends a fortune on ESD protection. One reason:
> > increased reliability and product life.
> >
> > A couple decades ago, I worked at a small electronics place where the
> > owner was very opposed to spending any money "on that nonsense". We had
> > a lot of product failures and our repair business was great. The
> > customers were not happy, though!
> >
> > I pushed for basic ESD procedures and got them through the engineering
> > manager. We used AS mats and wrist straps, AS bags and conductive shield
> > bags for completed PCAs. ICs stayed in the tubes, not poured out into
> > cardboard bin boxes.
> >
> > The results came slowly but we saw far fewer repairs and DOA product.
> > The customers started smiling. Business got better and better....
> >
> > You may get away with ignoring AS procedures, but it WILL get you sooner
> > or later!
> >
> > A wrist strap and a conductive work surface is a real small investment
> > compared to having to replace even one IC or having your gear freak out
> > at a gig.
> >
> > Major electronics manufacturers even install AS floor tile and make
> > assemblers wear AS slippers. They would not spend big $$$ if they did
> > not have statistical proof of the effectiveness of AS procedures.
> >
> > ICs contain extremely fine structures and a static charge, even one you
> > don't notice, is like a bolt of lightning!
> >
> > Debate (if any) closed.
> >
> > Regards.
> > -------------------------
> > John Blacet
> > Blacet Research Music Electronics
> > http://www.blacet.com
> > -------------------------
> > blacet at monitor.net
> > -------------------------
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> > http://www.blacet.com/mailform2.html
> >