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 Post subject: Multiple pad footprint
PostPosted: 02 Apr 2012, 10:42 
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Joined: 13 Jun 2011, 23:35
Posts: 55
I need to make a "Multiple pad footprint".

I've been trying to make a "universal" trimpot footprint for say a Bourns 3886 and 3296 (in same footprint) but am running into a problem with the pad numbering.

I need to lay out several pads and have them be assigned the same logocal pad number. For instance lay out 3 pads in a "triangle" formation with .2" spacing and lay out 3 pads in row formation with .1" spacing then somehow assign/connect/associate 2 sets of pads each as "pad-1" ("pad-2" and "pad-3")

I've spent several hours messing around but I cannot find a way to assign multiple pads one pad number, the closest I can get right now is to make a footprint with 6 pads, assign 3 of them as 1,2,3 then when I'm in PCB Layout I connect the floaters at that time, but it's a very un-elegant way to have a multiple pad footprint.

Is this even possible in DipTrace? and if not, anyone got a workaround for it? another way to accomplish more than one pad connected "as one pad"?


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 Post subject: Re: Multiple pad footprint
PostPosted: 03 Apr 2012, 08:51 
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Joined: 14 Jun 2010, 06:43
Posts: 2760
Pads with the same number isn't good idea. You can create pads with different numbers, but assign two or more pads to single component pin.

For example, component has pins 1, 2, 3, pattern has pads 1A, 1B, 2A, 2B, 3A, 3B. You should assign pin 1 to pads 1A and 1B, and so on. To do it, load component in Component editor, open "Attached pattern" window, select attached pattern and drag connection from pin 1 to pad 1A, then from pad 1A to pad 1B. Connect other pins in the same way.


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 Post subject: Re: Multiple pad footprint
PostPosted: 03 Apr 2012, 15:16 
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Joined: 13 Jun 2011, 23:35
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Alex wrote:
Pads with the same number isn't good idea. You can create pads with different numbers, but assign two or more pads to single component pin.

For example, component has pins 1, 2, 3, pattern has pads 1A, 1B, 2A, 2B, 3A, 3B. You should assign pin 1 to pads 1A and 1B, and so on. To do it, load component in Component editor, open "Attached pattern" window, select attached pattern and drag connection from pin 1 to pad 1A, then from pad 1A to pad 1B. Connect other pins in the same way.


Ok thanks Alex, I'll try that.

-- 10 Apr 2012, 08:43 --

That worked well, still had to connect the extra pads in PCBLayout but no big deal, got the job done.


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 Post subject: Re: Multiple pad footprint
PostPosted: 23 Jul 2012, 10:48 
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Joined: 14 Jun 2012, 06:00
Posts: 20
I have used this solution too, but had some issues with it.
1. Component Editor's (V2.2.0.9) Library Verification reports such pads to be unconnected, and they are not highlighted in "Attached Pattern" dialog when the pin is selected. Is it possible to define such multi-connections using Connection List in this dialog?
2. I can not find, how to connect pads at the different board sides. Is it possible?
3. Will PCB Layout check that this pads actually connected at the PCB?
4. Is there any way to connect pads at the level of Pattern Editor? Some components share the same pattern, and this way looks preferable.


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 Post subject: Re: Multiple pad footprint
PostPosted: 30 Jul 2012, 05:00 
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Joined: 14 Jun 2010, 06:43
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Hi Oleg,

1. No
2. If pads are over each other, it seems impossible
3. Check net connectivity in PCB Layout will report about an error. You will have to either route trace between pads or ignore the error.
4. There is no way to connect pads in Pattern editor.


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 Post subject: Re: Multiple pad footprint
PostPosted: 31 Jul 2012, 10:26 
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Joined: 14 Jun 2012, 06:00
Posts: 20
Thank you, Alex.
And another question. I am using IC (Semtech SC202A), which has land pattern with multiple pads connected by the polygon:

Attachment:
3.PNG

But design rules check marks this as error (pads too close to copper?). Options "Check Same Pattern Pads" and "Check Same Net Pads" are switched off .
Is it possible to workaround it, or i just need to ignore this errors?


You do not have the required permissions to view the files attached to this post.


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 Post subject: Re: Multiple pad footprint
PostPosted: 01 Aug 2012, 09:07 
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Joined: 14 Jun 2010, 06:43
Posts: 2760
You can either create complex polygonal pads (instead three pads + shape) or ignore DRC errors in PCB Layout.


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 Post subject: Re: Multiple pad footprint
PostPosted: 01 Aug 2012, 16:18 
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Joined: 16 Feb 2012, 16:52
Posts: 59
Alex wrote:
To do it, load component in Component editor, open "Attached pattern" window, select attached pattern and drag connection from pin 1 to pad 1A, then from pad 1A to pad 1B. Connect other pins in the same way.


Hello

I notice when I use this method that the pattern doesn't show connectivity when used in the layout. When hovering the mouse over the pads they don't show they are supposed to be connected...only ONE of the pads does (one the connected pad lights up as RED but the others don't). Is this expected? I'm sure to get LVS errors....

OR

Is it possible to build the pattern with pads that are not numbered? I don't necessarily have to have connectivity on the surface mount pads.

Thanks

jom


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 Post subject: Re: Multiple pad footprint
PostPosted: 02 Aug 2012, 09:17 
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Joined: 14 Jun 2010, 06:43
Posts: 2760
If I place a component with internal connection between pads directly in PCB Layout (not in Schematic), there is connection between pads that were internally connected in Component editor.

No, it is not possible to create pattern with pads that are not numbered.


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 Post subject: Re: Multiple pad footprint
PostPosted: 02 Aug 2012, 10:42 
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Joined: 16 Feb 2012, 16:52
Posts: 59
Alex wrote:
If I place a component with internal connection between pads directly in PCB Layout (not in Schematic), there is connection between pads that were internally connected in Component editor.

No, it is not possible to create pattern with pads that are not numbered.


I don't know what you mean by "internally" connected in Component editor.

So I'm going to get specific. I have a slide switch that should have 3 pins in the component but the pattern has 7 pads. So I added a 4th pin to the component. I then used your method when I attached the pattern. I went from pin 4 to pad 4. Then from pad 4 to pad 5 and so on.

Now when I placed the pattern in my layout and hovered the mouse over pad 4 it does NOT light up RED on pads 5, 6 and 7 as if the were not supposed to be connected. So then if I do connect these pads in the Layout editor I'd expect an error, right?

Thanks

jom


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