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

[Tristan Upton]

Ooop, in paragraph 2 I mean't to say: 

It is the high voltages typically involved in static discharge, combined 
with a path of HIGH conductivity, that leads to high currents between the IC 
pins and damage to the circuit inside. 

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

Tristan writes: 

> Hi Julian, 
> 
> If you are concerned about static then you should always try to keep
> ICs in their antistatic tubes, antistatic bags and/or in antistatic
> foam (usually black or pink). Do not store them loose in plastic
> drawers or in white polystyrene foam! Some people spray polystyrene
> foam with a conductive coating or cover it with foil but these are not
> a good solution as the high conductivity can be a problem if a static
> charge is applied. 
> 
> The materials used in antistatic bags and foam etc are conductive but
> have a relatively low conductivity. If you touch the antistatic
> material when you are statically charged the charge spreads through
> the material slowly, thus only producing a small local differential
> between pins on ICs. It is the high voltages typically involved in
> static discharge, combined with a path of low conductivity, that leads
> to high currents between the IC pins and damage to the circuit inside. 
> 
> For best protection you should also use an antistatic bench mat where
> you are working and an antistatic wrist strap. The antistatic mat
> should be grounded to your electrical earth through at least several
> Meg ohms and your wrist strap should be connected to the mat or ground
> through several Meg ohms as well. Synthetic clothing and shoes can
> also generate or allow the build up of static charge on your body, as
> can walking across synthetic carpets etc. 
> 
> In the electronics labs where I work all benches and flooring have
> antistatic coatings and we are required to wear antistatic shoes or
> heel straps while working in the lab. The benches and equipment racks
> also have antistatic wrist straps to use when handling boards and ICs.
> Despite all these precautions I have still seen boards destroyed by
> careless people taking off synthetic clothing. 
> 
> -- 
> Best regards,
> Tristan                            mailto:tu at alphalink.com.au 
> 
> Thursday, May 29, 2008, 10:07:41 AM, you wrote: 
> 
> J> Im having a bit of a tidy up at the moment, and have a load of ICs to deal with . 
> 
> J> Most of my other components are stored in draw things, a bit like this - 
> 
> J> http://www.toolspecial.com/images/550_3.jpg 
> 
> J> but evrey time i order any ICs at all now, they seem to come in
> J> anti-static bags as standard.... so thats got me to wondering
> J> if i 
> J> should worry too much about all this in storage? 
> 
> J> Somthing ive also wondered - in a conductive bag, surely if theres
> J> an issue with static, without proper grounding, the whole
> J> lot get 
> J> 'zapped' insted of just individuals?  As you may have gathered, i
> J> dont know much about this... ! : ) 
> 
> J> Julian  
> 
>  
> 
> 
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