[PCB_FORUM] Re: Dual Plane VIA Connection Question
- From: "Andrew W. Riley III" <drew3rdof3@xxxxxxxxxxxx>
- To: <icu-pcb-forum@xxxxxxxxxxxxx>
- Date: Sat, 11 Mar 2006 14:56:07 -0800
Vincent,
Remove the vias from the pads in question. Edit the plane on the external
layer
and 'Void' > 'Auto'. The real issue is that you may have to reduce the value
in
"Suppress Shapes Less Than:" box to something like 0.005 in the 'Shape' >
'Parameters' window. You might want to remember that value or put it back when
you are done especially if there is something like ground fills on the external
layers in your design. Also, you may have to undo and play with other settings
in the 'Shape' > 'Parameters' window until you like what you see as the
void-auto will draw tracks to connect the pad.
An alternative to the void-auto option is to edit the boundary and/or vertex to
give the fill a thermal connection to the pad. Just make sure the fill is over
the center of the pad in question so that it connects to the net.
Cheers!
Drew
----- Original Message -----
From: Vince Di Lello
To: icu-pcb-forum@xxxxxxxxxxxxx
Sent: Saturday, March 11, 2006 2:27 PM
Subject: [PCB_FORUM] Dual Plane VIA Connection Question
Here's hoping one of you great designers out there (and Allegro expert) can
help
me out . in the picture below you will see a light blue external (Top Side)
3.3V
plane. Inside this board (but not shown) is a separate 3.3V plane. What I would
like to do is have the (3) vias at the top of the picture (coming off the
electrolytic cap) make connection with the internal 3.3V plane and then connect
to the electrolytic cap with traces as shown in the picture. The 3.3V then
travels down this small external plane coming into contact with some other
capacitors and ultimately ends at the two vias at the bottom which carry the
current from the top side of the board to the bottom side of the board where in
turn there are two traces that connect to two bottom side pads of a bottom side
connector. Now for my problem - the two vias at the bottom of the light blue
area are now also connected to the INTERNAL 3.3V master plane (for clarity sake
I did not turn that plane on). I DO NOT WANT them to connect to the internal
3.3V plane. I want to force the 3.3V signal to have to travel through the caps
and then into the connector pads on the external layer only. Is there a setting
or a property that I can add to those two vias so that they get connected to
the
small external 3.3V copper plane, but NOT to the INTERNAL 3.3V master plane?
Any help, especially on a weekend, would be greatly appreciated. Thanks in
advance and I hope all who are listening will have a great weekend - at least
what is remaining of it. Thanks again.
Vincent Di Lello, CID+
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