Re: gEDA-user: pcb join pad to polygon

[Peter Clifton <pcjc2@xxxxxxxxx>]

On Sun, 2010-02-07 at 08:04 -0800, Ben Jackson wrote:
> On Sun, Feb 07, 2010 at 09:18:35AM -0500, gene glick wrote:
> > I made a polygon on the top layer, and I want to place a component pad 
> > within the polygon.  Is there a way to make it connect without adding a 
> > trace?  By default the tool places a clearance gap around the pad - so 
> > it doesn't touch.
> 
> Are you sure you want 100% connection like the other reply suggested?
> That can be very hard to solder, especially on a multilayer board where
> the top is well "stitched" to internal ground layers.  I really think
> pads should have the same "thermal" feature that pins do, but since they
> don't I just draw lines and set *them* to merge with the poly.  If I want
> low impedence I just make a "+" of wires.

I would typically use the solid connection for things like a bolt-down
transistor, or other heat-sink type connections - although soldering
would be a pain, probably requiring pre-heat and reflow.

I kind of assumed you were working with a transistor of some kind.

For 0.01 Ohm sensing, you probably want to attempt at making a kelvin
connection, see http://www.edn.com/article/CA502424.html

Specifically, look at the component footprints suggested in Figure 2.
Article in PDF format: http://www.edn.com/contents/images/21705di.pdf

Best regards,

Peter C.



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