Thanks for explaining to everyone how unique my "challenge"
is, but I would think others have faced similar situations.
I'm not really asking anyone to solve my problem for me, and
it this unique application doesn't really warrant buying and
learning a thermal simulator, but it just makes me wonder how
other people treat the problem.
Many people I'm sure have multiple currents on a board.
(I don't think ALL of us are doing 2.5V digital designs)

If you assume the chart or calculator is for a single trace,
and you have TWO traces, do you:
1) use the single trace values?
2) increase the width a little?
3) try to leave space between them?
4) simulate it?

So its kind of a POLL.
What do YOU do?

just curious,
Jack






On 5/9/07, Brooks,Bill <[log in to unmask]> wrote:
>
> Generally most boards do not have the same conditions that Jack is
> describing to the group. This is a specialized application and I would
> recommend doing a thermal model of the board before making any
> assumptions.
> We use a program called ICEPACK
>
> (http://www.ansys.com/products/icepak/default.asp )
>
> along with our Solidworks 3D model of the board assembly which is a direct
> output from the Altium Designer board design program and we can plug
> thermal
> temp and conductivity values into the board assembly and predict what the
> temps will be at any given ambient in any enclosure we design.
>
> The challenge facing Jack is predicting what the total load of heat will
> raise the temperature to hoping of course that it does not exceed the Tg
> of
> the board material.
>
>
> Bill Brooks
> PCB Design Engineer, C.I.D.+
> Tel: (760)597-1500 Fax: (760)597-1510
> Datron World Communications, Inc.
> Vista, California
>
>
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