Jeremy, Yes, that's the configuration - and we think the corner is around 300Khz. Good point - thanks, Jim -----Original Message----- From: Jeremy Plunkett [mailto:jeremy@xxxxxxxxxxxxxxx] Sent: Wednesday, December 15, 2004 10:51 PM To: james.f.peterson@xxxxxxxxxxxxx; si-list@xxxxxxxxxxxxx Subject: RE: [SI-LIST] Re: Chassis and Signal ground Jim, In your existing products do the thermal ground shapes overlap with signal ground as seen in the board layout(ie topview)? If they do then depending on the dielectric thickness between them you may already have pretty high coupling between them at high frequencies due to the plane capacitance. In this case combining them would only make a difference at DC and low frequencies where you may find the emi/esd less of a problem. Jeremy ------------------------------------------------------------------ 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?Si-List_FAQ 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