We had a similar situation years ago.  In our case, we used
multiple vias off an enlarged track to help distribute the current.
In our case, I believe, we had to handle about 30 amps.  We
used as many vias (~20) as we could fit into that area and never
had a failure.

Hope this helps somewhat.

Larry Campbell
Supervisor, PWB
BFGoodrich, Avionics Systems

>>> David Baldwin <[log in to unmask]> 06/19/98
01:24pm >>>
Designers Council:

I am designing a board which has heavy current devices,
required to handle
10A max peak.  The board will be constructed using 2 oz. copper.

IPC-D-275 5.3.2.3. states:

"Total cumulative copper web for all layers in any plated through
hole
should not exceed .160" for 1 oz. copper, or .080" for for 2 oz.
copper.

The total of the thermal relief cross sectional area divided by the
number
of planes connected to the plated through hole, shall not violate
current
carrying capacity requirements for a given hole.

If the individual web width violates the intended minimum
conductor width
it shall be specified on the master drawing."

If I use the web width calculations, or even the .080" max web
width for 2
oz copper, it's not going to handle the current without getting
really hot.
 If I connect the hole directly into the plane, we'll have a difficult
time
soldering it.

What is your recommendations and experience with this type of
situation?

Thanks in advance for your advice and input.

David Baldwin
____________________________________

   PCB Designs by Baldwin Tech.
(602) 812-9246  FAX (602) 812-9247
   http://www.neta.com/~btech
____________________________________

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