[SI-LIST] Re: Pulse current handling capability of PCB
- From: Jack Olson <pcbjack@xxxxxxxxx>
- To: steve weir <weirsi@xxxxxxxxxx>
- Date: Tue, 15 Sep 2009 09:43:06 -0500
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
>
>
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