[SI-LIST] Re: IPC-2152 trace current/temperature calculator
- From: Jack Olson <pcbjack@xxxxxxxxx>
- To: SI-LIST <si-list@xxxxxxxxxxxxx>, dbrooks9@xxxxxxxxxxxxxxx
- Date: Wed, 13 Jan 2010 10:45:46 -0600
Not to complain (kudos for developing the calculator!)
but since proximity to planes has the most drastic effect
over any of the other factors, and it is a fairly linear
relationship, I'm curious why you didn't incorporate it.
(only one extra box!) of course, not knowing about splits
and "swiss cheesiness" of the plane, maybe you were
simply afraid? (grin, kiddin' ya)
There is a graph in this article if you are interested:
http://frontdoor.biz/PCBportal/HowTo2152.pdf
Unless I'm misunderstanding your calculator, I think your
result will be about 50% WRONG in most cases (since
most boards have planes these days)
just trying to help,
keep up the good work,
Jack
> From: dbrooks9@xxxxxxxxxxxxxxx
> Subject: [SI-LIST] Re: IPC-2152 trace current/temperature calculator
> Date: Tue, 12 Jan 2010 22:38:19 -0700
>
> I don't know if you have read the standard. There are a couple of= pages
> that address thermal modeling, planes, alternative dielectrics, etc,= in a
> very general manner. There are no quantitative adjustments included (= with
> the possible exception of how to treat parallel conductors which is pr=
> etty
> straightforward, and pretty obvious.) There is a Figure A-13 that rela= tes
> to some estimated factor adjustments that can be used based on the dist=
> ancebetween the conductor and a plane for 1 Oz traces in .070 thick Polyim=
> ide Board (and a single curve for 2 Oz traces). The calculator does n= ot
> incorporate these adjustments in its calculations. But these adjustments=
> caneasily be made to the calculated results if desired. Overall, the gene=
> ralities included in the Standard apply equally well to the calculated
> resu=
> lts from the calculator.
> The Calculator is based o= n Conductor Sizing Charts contained in the
> Appendix (from Figure A-17, p 35= to Figure A-86, p83).
>
> Doug
>
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