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Reply To: | TechNet E-Mail Forum. |
Date: | Thu, 25 Dec 2003 07:35:00 +0200 |
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Hi,
As far as I remember IPC allow 10% variations in copper thickness.Take into
account that 2 oz is unit based on weight while you are describing
thickness.Add to this topography of the foil from lamination side, thickness
reduction as result of different surface preparation processes - it seems
you need X-mass miracle to get to 4% while you are expecting 0.4%.
Good luck and Happy New Year
Edward
> -----Original Message-----
> From: Carl VanWormer [SMTP:[log in to unmask]]
> Sent: ד דצמבר 24 2003 17:16
> To: [log in to unmask]
> Subject: [TN] Question on 2-oz Copper uniformity for current sense
> resistor
>
> I have a project that seems to be a good candidate for a current sense
> resistor made as a part of the PCB. I am using the free calculator,
> PCBTEMP, from the UltraCAD website (http://www.ultracad.com/calc.htm) for
> geometry calculations. I need to know the expected variability in
> thickness,
> batch to batch, for the copper foil on 2-oz stock. I can live with the
> 0.4%
> TC of the Cu, but I need to evaluate all the other variables in my error
> budget before I present my proposal. I would appreciate any success (or
> horror) stories from people who have (not) used the board copper as a
> current sense method.
>
> Thanks,
> Carl
>
>
>
> Carl Van Wormer
> Cipher Systems
> 1815 NW 169th Place, Suite 5010
> Beaverton, OR 97006
> Phone (503)-617-7447 Fax (503)-617-6550
>
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Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315
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