--- Benoit Nadeau <[email protected]> wrote: > > Bonjour de Montreal, > > In another life, I was working for a EMC Test lab > and we always used the > step by step procedure which was in the ESD > Standard. We tested using this > procedure for years and we did encounter some > products who failed at low > level ESD but had no problem at higher levels. > > We wondered what to conclude and had some > hypothesis. > > 1) may be the current path was different at higher > level or > 2) Lower levels might have a slightly longer rise > time which tends to produce > more energy in the lower part of the frequency > spectrum where the EUT was > more sensible. >
Partly true. The risetime changes as the voltage increases. The risetime "slows" (dV/dt or dI/dt value gets reduced) down as you begin to go over 6-8kV. I also have seen products fail at 2-4 kV and pass at levels 8-10 kV. This ofcourse is on air discharge equipment where variability of the risetime is expected. Contact discharge equipment do not exhibit much risetime variability (at least not to a large degree) Hans T. Mellberg EMC/ESD Consultant member ANSI/IEEE C63.16 WG on ESD __________________________________________________ Do You Yahoo!? Bid and sell for free at http://auctions.yahoo.com --------- This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to [email protected] with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to [email protected], [email protected], [email protected], or [email protected] (the list administrators).
