[sdiy] Storing ICs (and static sensitivity) - how much to worry?

[Tristan]

Hello Alan,

You are right, there is also the faraday effect. I guess I was talking
about the dissipative type of materials. I did a bit of googling and
there certainly seems to be a variety of approaches to static control.
The important thing is to use antistatic materials and procedures if
you want to avoid damaging your ICs. Some people may not care about
it, but that is their choice.

-- 
Best regards,
Tristan                            mailto:tu at alphalink.com.au

Thursday, May 29, 2008, 11:05:05 PM, you wrote:

NA> I have a big problem with this explanation, even after inserting the
NA> supplied correction.

NA> An antistatic bag may measure a few hundred kOhms from corner to corner,
NA> I do not believe that this is enough to slow down any charge front, and
NA> if it did, it would result in the very thing you are trying to avoid -
NA> pins at significantly different voltages.
NA> As I understand it, the packaging attempts to provide some form of
NA> Faraday cage around the device; no matter what static voltage is
NA> applied, all the pins need to be maintained at the same potential, even
NA> if that is 1000's of volts above ground. Aluminium foil would be ideal
NA> IF you could guarantee a connection to every pin.

NA> ~~~Snip~~
NA> The materials used in antistatic bags and foam etc are conductive but
NA> have a relatively low conductivity. If you touch the antistatic
NA> material when you are statically charged the charge spreads through
NA> the material slowly, thus only producing a small local differential
NA> between pins on ICs.
NA> ~~Snip~~
NA> It is the high voltages typically involved in static discharge, combined
NA> with a path of HIGH conductivity, that leads to high currents between
NA> the IC pins and damage to the circuit inside.
NA> ~~Snip~~

NA> _____________________________________________________________________
NA> The information contained in or attached to this email is
NA> intended only for the use of the individual or entity to which it
NA> is addressed. If you are not the intended recipient, or a person
NA> responsible for delivering it to the intended recipient, you
NA> are not authorised to and must not disclose, copy, distribute, or
NA> retain this message or any part of it. It may contain
NA> information which is confidential and/or covered by legal
NA> professional or other privilege (or other rules or laws with similar
NA> effect in jurisdictions outside England and Wales).
NA> The views expressed in this email are not necessarily the views
NA> of Centrica plc, and the company, its directors, officers or
NA> employees make no representation or accept any liability for its
NA> accuracy or completeness unless expressly stated to the
NA> contrary.

NA> Centrica plc

NA> Registered office: Millstream, Maidenhead Road, Windsor, Berkshire SL4 5GD

NA> Registered in England and Wales No 3033654