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| Date: | Sat, 15 Mar 1997 19:31:00 -0500 |
| Content-Type: | text/plain |
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K.Varadaraj@CADET, India. wrote:
>
> Hello
>
> I would like to know if fabricating an SMD (double side mount), Six layer
> PCB, which has a 50 mil pitch pin to pin and 100 mil pitch row to row, 44
> pin connector, is possible any where. The drill provided is 30 mil and the
> pad is 32mil x 80 mil, oblong. Six mil track is routed between the pins.
>
> We have had a vendor fabricate this board here in India and due to process
> tolerances, the yeild is very less or almost has been nil.
>
I recommend the following:
1. choose a smt-connector instead of a drilled one.
2. Donīt route traces between the pins. Because of the total fabrication
tolerances of 8-10 mil and layer misregistration the risk of shorts
between drilled holes and adjacent traces on inner layers is very high.
Rainer Taube
TAUBE ELECTRONIC
http://www.taube-electronic.de
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