I am only familiar with the IPC minimum recommendations and various articles in trade publications that refer to that. (so I've never seen that equation.) Where can I learn more about this specific subject? I mean, how did you derive that 100W/sqin for 20us? What if he had said 40us? 200us? What if he had said 10Hz? 100Hz? That's a subject I'd like to know more about... Jack . On Tue, Sep 15, 2009 at 7:50 AM, steve weir <weirsi@xxxxxxxxxx> wrote: > Assuming whatever is connecting to this is not limiting, then the rule > of thumb is: > > Resistive loss density = I^2*0.5mW/( copper_weight * trace_width^2 ) where: > > resistive loss density is W/sq in > copper weight is in oz / sq ft. > trace width is in inches > > For even something as short as 20us I would stay below 100W / sq in. > > Steve. > Deepak V.L wrote: > > Hi Havermann, Pls find the answers below > > > > -is this a periodic surge event (>1Hz) or will it just happen "once a > day"? > > It is not a periodic surge, It can happen only once when the system is > > switched on. > > > > -is this surge current the only current on this trace? > > Yes > > > > -are there other traces on the surrounding area that might coheat this > > trace? > > No > > > > -whats the copper weight? > > 1 oz > > > > -on which layer of how many layers > > The traces are in the external layers (dobulb sided board) > > > > Thanks, > > Depak > > > > > > ----- Original Message ----- > > From: "Havermann, Gert" <Gert.Havermann@xxxxxxxxxxx> > > To: "Deepak V.L" <deepak.vl@xxxxxxxxxxxxxx>; <si-list@xxxxxxxxxxxxx> > > Sent: Tuesday, September 15, 2009 5:46 PM > > Subject: AW: [SI-LIST] Pulse current handling capability of PCB > > > > > > Dear Deepak, > > > > This depends on many factors: > > -is this a periodic surge event (>1Hz) or will it just happen "once a > day"? > > -is this surge current the only current on this trace? > > -are there other traces on the surrounding area that might coheat this > > trace? > > -whats the copper weight? > > -on which layer of how many layers > > > > > > > -------------------------------------------------------------------------- > > Absender ist HARTING Electronics GmbH & Co. KG; Sitz der Gesellschaft: > > Espelkamp; Registergericht: Bad Oeynhausen; Register-Nr.: HRA 5596; > > persönlich haftende Gesellschafterin: HARTING Electronics Management > GmbH; > > Sitz der Komplementär-GmbH: Espelkamp; Registergericht der > > Komplementär-GmbH: Bad Oeynhausen; Register-Nr. der Komplementär-GmbH: > HRB > > 8808; Geschäftsführer: Torsten Ratzmann > > -----Ursprüngliche Nachricht----- > > > > Von: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] > Im > > Auftrag von Deepak V.L > > Gesendet: Dienstag, 15. September 2009 13:51 > > An: si-list@xxxxxxxxxxxxx > > Betreff: [SI-LIST] Pulse current handling capability of PCB > > > > > > Dear Experts, > > Could someone please guide me how to select a trace width for carrying a > > 100A surge current for 20us over a PCB trace ? > > > > > > Thanks in advance, > > Deepak > > ------------------------------------------------------------------ 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 technical documents are available at: http://www.si-list.net 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