On 2 Oct 2003 at 16:44, Alex Krstic wrote: > > > Hi all. Simple question yet I haven't read the definitive answer. Is > damage from ESD cumulative? Reason I ask is the following statement I > came across in a GaAs MMIC article. [...] > > I've always preached that ESD damage is cumulative. > > Alex "Shocked" Krstic > NovAtel Inc. I would say it depends. Usually I think we are on the safe side if we assume it's cumulative unless the basic physics state there is no degradation. My favourtite example: Remember the big varistors in power supplies. If the power line _has_ transients, the varistors _will_ degrade more and more, until the leak current is high enough for incineration (thus, industry began to make special varistors with incorporated irreversible thermo fuse). Other side, if you know your transients are short enough and energy limited, you can live with suppressor diodes instead, please the _big fat expensive_ ones, and they will not degrade unless your transients exceed the maximum ratings. If they die, they don't die slowly by unsoldering themselves or roasting your power supply slowly, they die spectacularely and leaving usually with a rock solid short. I would say the same conclusion can be made for any device. If the construction can dissipate the energy of a discharge, I would assume no cumulative damage (and there is the little difference between a suppressor diode and a FET gate). Regards Matthias Mansfeld -- Matthias Mansfeld Elektronik * Leiterplattenlayout, Bestueckung Am Langhoelzl 11, 85540 Haar; Tel.: 089/4620 093-7, Fax: -8 Internet: http://www.mansfeld-elektronik.de GPG http://www.mansfeld-elektronik.de/gnupgkey/mansfeld.asc --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 -----------------------------------------------------