Mike, if you would be so kind as to indulge me here, I would like further details on the sort of situation that justified BC for ESD control. Can you cite ballpark numbers where absent BC, the plane impedance was too high and a destructive event was only correctable by pulling the impedance down with BC? Regards, Steve. >Your comment: >If it is indeed what you said below that BC only improves the margin on a >properly stackup PCB. I would suggest a better margin can be achieve even >without >BC by simply removing your oh so proud isolated chassis ring and have direct >tight connection between chassis and logic reference on PCB. >******** >My prior comment: >Perhaps the explanation I offered was not explicit enough for you. The "50-60 >different designs" I referred to had ESD susceptibilities and yes, some of >them were not well layed out to start with; however, even well designed >boards >improved their margins of susceptibility using BC construction. (NOTE: The >"well layed out" boards were improved by the use of BC With or WITHOUT >chassis >ground rings.) >******** ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List FAQ wiki page is located at: http://si-list.org/wiki/wiki.pl List technical documents are available at: http://www.si-list.org List archives are viewable at: //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu