On Thu, 16 Oct 1997, Jon Bertrand wrote:

>      What do you do when your design is wimmpy?
>
>      1)  Read "Noise Reduction Techniques in Electrical Systems"  Henry W.
>      Ott, John Wiley and Sons, ISBN 0-471-85068-3

Where i work he came in to give a lecture on EMC workbench tesing.  He is
a fountain of knowledge.  Buy the book!


>
>      2)  Read it again.
>
>      3)  If you have $1000 to invest in your education (the best damn $1000
>      you'll ever spend...), look up the Univerisy of Missouri-Rolla,
>      Electrical Engineering department, EMC lab, (say Prof. Tom Van Doren).
>      Then sign up for one of their classes on EMC.
>
>      4)  Buy a Schaffner NSG 435 ESD gun (the best damn $8500 you'll ever
>      spend).  Don't be a affraid to crank it to 16KV and hit everything a
>      hundred times.
>

I don't know if you have to spend that much on an ESD gun!  Well, i think
Ott had shown a much much cheaper one at the lecture.


>      5)  Pay extra attention to the "loop areas" in your PC layout.  Reduce
>      them as close to zero as possible.  That means putting caps of the
>      correct value in the correct place.  On two layer boards everything
>      becomes "close pairs of signal and return lines."
>
>      6)  Partition your loop areas.  Keep the dirty loops from the clean
>      loops, or the outside world loops from the inside world loops, or the
>      Hit-by-ESD loops from the not-hit-by-ESD loops.
>
>      7)  Use resistors, diodes, and caps to stear any ESD energy around
>      your circuit let it return on it's return line (i.e. minimize the ESD
>      loop areas).
>
>      8)  Trust nothing.  Every line into your processor is a line that can
>      corrupt you.  Put resistors on them all.  Limit all unneeded bandwidth
>      on every line with RC filters.
>
>      In the end you may add $1.50 to your design but I'll be worth it.
>
>      If you need more info email me directly.
>
>
>
>
>      Jon Bertrand
>      jonb@cirris.com
>