[SI-LIST] Re: Why Thumb rule 40 mils takes 1A
- From: Jack Olson <pcbjack@xxxxxxxxx>
- To: SI-LIST <si-list@xxxxxxxxxxxxx>
- Date: Wed, 8 Dec 2010 12:10:39 -0600
The ancient IPC chart has been replaced by IPC-2152 "Standard for
Determining Current Carrying Capacity in Printed Board Design".
Here's a more useful article than most (tooting my own horn), with an
attached spreadsheet:
http://HowToPCB.net/HowToPCB-Trace&Space.html<http://howtopcb.net/HowToPCB-Trace&Space.html>
page down to the "Conductor Width" section.
hope it helps,
Jack
> ------------------------------
>
> Msg: #5 in digest
> Date: Tue, 07 Dec 2010 04:40:52 -0800
> From: steve weir <weirsi@xxxxxxxxxx>
> Subject: [SI-LIST] Re: Why Thumb rule 40 mils takes 1A
>
> It depends on:
>
> Acceptable temperature rise.
> Acceptable absolute temperature.
>
> Both of those values feed from your expected product life time. If the
> product only has a 90 day warranty and your customers have low
> reliability expectations, then your first concern will only be
> preventing a fire. The ancient temperature rise versus track width /
> weight charts are still published by the IPC. You can probably also
> find them online for free.
>
> Steve.
> Vijay Anand wrote:
> > Dear All,
> > I have a Giga POE signals which is routed on 4 width, 5.5 space and 1.8
> mil
> > thickness. I have loaded up to 1A in that lines. Initially I thought the
> > track will damage (since the thumb rules says 40 mils takes 1A) but it
> > didn't happen the way I thought. My doubt is what is the actual
> current
> > carrying capacity for 40 mil and 4 mil? Is there is any rule on the
> track
> > width for the PHY signals which has POE.
> >
> > Please share your experience.
> >
> > Thanks and Regards,
> >
> > Vijay
>
>
> --
> Steve Weir
> IPBLOX, LLC
> 150 N. Center St. #211
> Reno, NV 89501
> www.ipblox.com
>
> (775) 299-4236 Business
> (866) 675-4630 Toll-free
> (707) 780-1951 Fax
>
>
>
> ------------------------------
>
> Msg: #6 in digest
> Subject: [SI-LIST] Re: Why Thumb rule 40 mils takes 1A
> Date: Tue, 7 Dec 2010 14:00:35 +0100
> From: "Viklund, Per" <Per_Viklund@xxxxxxxxxx>
>
> The original IPC charts are (generally) a bit conservative and one
> really has to make sure the application falls within the boundary
> conditions of the charts.
>
> Michael Jouppi made lots of investigations on this topic and has
> published numerous papers (Google his name) on current capacity of PCB
> traces.
>
> A good paper on PCB007 on the issues of estimating current carrying
> capacity: http://www.pcbdesign007.com/pages/zone.cgi?a=50249
>
>
> /Per Viklund
>
>
>
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