We have a product that is deployed around the world and is in the human-ESD discharge path. We are experiencing problems with an occasional CPLD shorting out internally which, of course, requires a field replacement of the entire controller. This plastic enclosure, membrane keypad equipped product has tranzorb protection on all keyboard lines, and the tranzorbs are not bad on the returning units. I cannot kill components on good controllers with
16kV spikes, even directly to the membrane keyboard signals on the board. (although the processor will reset essentially every time)Does the list have an opinion as to the voltage I should actually be testing at? What voltage do all of you test your embedded designs at? Is 16kV too low to test/ design keypad controllers at?
And does the list have an opinion on placing a grounded grid outer- most on the membrane keypad? Do any of you do that religiously? I am getting mixed opinions to this question which seems obvious to me (do the grounded grid).
Thanks in advance;
Chris