[sdiy] electrosensitive devices

[Peter Grenader]

Many suppliers, Mouser among them, put a blanket control system on all
semiconductors.  It's less expensive for them to put all semi's into the
costly nickel plated anti static bags than it is to concoct some large scale
sorting/segregation system, because it has to carry not only to the final
shipment, but through their entire warehousing/receiving system as well.
You can only imagine how hard it would be to assure that all static
sensitive parts, and only those parts, received special handling procedures,
are kept in a separate stores locations, etc.

So,  if you are unsure which are and are not problematic for static, as
impractical as this may be, the best solution would be to carry out their
system in your lab and for you to treat everything as static sensitive as
well.   Yeah, I know...a drag.

Problem is, and this came up a few months ago...99.99999999 to the tenth %
of the failures from the initial static discharge is not catastrophic.  It
merely degrades the part so it will lean towards infant mortality somewhere
down the road.  And when it does, it's hard to determine if ESD was the
cause unless you pop the top off and have a look under an extremely powerful
microscope. Even more impractical in my book.

Two general rules of thumb will help you out a lot:

1)  Treat static like a virus and take the necessary precautions to keep it
from spreading.

2)  Get your hands around which parts are and are not susceptible and make
damn sure you at least keep them in foam when not in boards and wear a
ground strap when inserting them or when handling a board that has them
inserted, even if you are planning of fooling with those parts directly at
the time. 

I worked for a company (Western Digital) whose first products were
controller LSI chips.  This is what they started off doing and what put them
on the map. This was years before they purchased the Tandon hard drive
division. You have no idea what you have to go through to create a truly
static free environment.  We're talking heels straps, nickel faraday bags,
heel straps, wrist wraps, conductive booties, grounded forklifts, grounded
storage racks, grounded soldering irons, air ionizers, conductive mats,
anitstatic spraying of work benches - it's a complete mess.

hope this helps - remember, it's not only 4000 series CMOS you have to worry
about!

Peter