If the need for thicker copper is to carry more current, be aware that the
"IPC - 2221 Generic Standards on Printed Board Design Figure 6-4" on page
38 is incorrect. Fortunately, it is approx. 4X off the real numbers,
which means you can run four (4) times the current through a trace (or
plane) for the same temperature rise. The new IPC Standard that is being
worked on is IPC- 2152. This will have very accurate charts to help you
size traces and planes. The Chairman of this group, Michael Jouppi, has a
web site just for PCB conductor sizing and thermal issues at www.
thermalman.com. It contains the complete sordid history as to how these
design curves got so messed up, but also good charts and data on what the
proper sizing should be.
So if the 2 oz or 3 oz innerlayers are for carrying more current, they may
not be required.
Happy Holden
Westwood Associates
Kitty Hines <[log in to unmask]>
Sent by: DesignerCouncil <[log in to unmask]>
04/06/2005 01:54 PM
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Subject
Re: [DC] PCB TECHNOLOGY (2 oz copper)
Jack,
Thanks for your input. This going to be a 16-layer board, (2) layers to
be 3oz, 6 layers to be 2oz., the rest will be 1oz. copper. The board is
.187 thick, so it is possible. I'm just trying to find out if there are
any issues I need to consider. Trace/space widths should be just fine, so
I guess I'm gonna go with it and see what happens!
Thanks Again,
Kitty
Hello all,
One of our PCB suppliers came out with a PCB design that have 2 ounces
of copper on all layers. Until now we have worked with PCB that have 2
ounces of copper only on the exterior layers, and only one ounce of
copper on the interior layers.
We do not have experience working with PCBs with 2 ounces of copper on
all the layers.
Would you mind helping us to gain more knowledge regarding these PCBs?
Are there any risks associated with this design: thermal events,
concerns, things that we should be aware of?
Thanks in advance,
..........................................................
Kind regards
Erika E. Sanchez
PCB Designer
Siemens VDO
Internet: http://www.siemensvdo.com
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