[PCB_FORUM] Re: Dual Plane VIA Connection Question
- From: "Vince Di Lello" <vince.dilello@xxxxxxxxxxxxxxxx>
- To: <icu-pcb-forum@xxxxxxxxxxxxx>
- Date: Sat, 11 Mar 2006 16:58:34 -0800
Les ... almost ... while that is the kind of solution I am looking for, we
unfortunately use positive planes. We find that using positive planes (and
getting a WYSIWYG) is more beneficial to us considering that we have quite a
few split planes.
Again though, thanks for the trick. I appreciate your help
Vincent Di Lello, CID+
________________________________
From: icu-pcb-forum-bounce@xxxxxxxxxxxxx on behalf of Les Wong
Sent: Sat 3/11/2006 3:51 PM
To: icu-pcb-forum@xxxxxxxxxxxxx
Subject: [PCB_FORUM] Re: Dual Plane VIA Connection Question
Vince:
Here is a trick I ave used to force a connection thru a specific via:
1. create a flash shape the size you want the antipad to be
2. save it to a name like: c35.ssm
3. copy your current padstack to a new name: xxx.pad
4. edit the padstack xxx.pad and use the c35.ssm as the thermal flash.
5. use this new padstack as the via you do not want to connect to the planes.
This will not allow the connection to the plane, as long as it is a negative
plane.
How does that sound ?
Les
Vince Di Lello <vince.dilello@xxxxxxxxxxxxxxxx> wrote:
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+
Other related posts:
