Re: Lets talk about input protection against ESD (human body).




Ge0rge Marutz wrote:

>I have a question about modeling the level of ESD that might affect my
>module and what type of low cost protection schemes might be used to
>harden it.
>
>My product is going to be an automotive assembly that has a remote push
>button interface to a microprocessor controlled "black box" stashed in
>the engine compartment. The push button can be whatever type my
>particular customer decides to use in their vehicle for that model /
>model year. It just needs to provide a momentary closure to ground to
>activate my product.
>
>1st question: How do I go about judging the level of static discharge
>that can come from a persons finger, through the switch body, and onto
>my wiring, when pushing this button? I assume the button will be in a
>plastic housing with a plastic button surface. I know this will be
>impossible for you to solve for me without knowing any details about
>the switch. I don't even have details about the switch yet. But, what
>steps do I need to go through once I do?
>
>I do not have the equipment for testing in-house so need to do
>everything on paper to the best of my ability first. I can then pay to
>send a design out to a test lab. I'm trying to design this right up
>front so I can minimize trial and error experimentation at an outside
>lab. This takes time and money I don't have.

Here are some references that may help you in deciding which standard
to design for and test to.

http://www.esda.org/basics/part5.cfm
http://www.st.com/stonline/books/pdf/docs/6970.pdf
http://www.technick.net/public/code/cp_dpage.php?aiocp_dp=guide_esd_005
http://standards.ieee.org/reading/ieee/std_public/description/emc/C63.16-1993_d
esc.html
http://www.semiconfareast.com/esdspecs.htm
http://www.semiconfareast.com/esdspecs2.htm


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