Author Topic: Net ties in internal layers - or alternative  (Read 2353 times)

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Offline ADJohnsonTopic starter

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  • Country: gb
Net ties in internal layers - or alternative
« on: August 09, 2019, 03:39:26 pm »
I couldn't find an answer to this but hopefully someone can give me a better workaround.  I have a 4 layer PCB with a 2 post TH PCB terminal on the top layer.  Pin 1 is -Ve (return to power supply).  On the top layer I connect a ground trace to the pin - NET PWRGRND.  On layer 2, I have a Ground plane which I want to connect at this pin.  On layer 3 I have another Ground plane which I want to connect to this pin.  The planes should NOT be connected to each other at any other location. 

Currently, I created a 3-pin NETTIE in the schematic and edited the footprint so that it had one SMD pad and two TH pads.  I then connected the grounds to a seperate pin of the NETTIE.  In the PCB this works: the SMD pad connects to the top trace, the other two pads route down the board and connect at each layer.  I can edit the pads to give a solid connection (i.e. no thermal relief) which works for the TH but not the SMD pad for some reason - the copper fill just flows around it, attaching at one edge.  Take a look at the image to see what I've currently got.  Red is top layer, Yellow is layer 2, Pink is layer 3.  The image was taken with layer 3 active; layer 2 pad is connected in exactly the same way to the yellow copper fill.

It'll work, but what I really want to be able to do is just tie the grounds to the pin at each layer - almost like I want a NETTIE on the internal layers.  I don't really want this NETTIE 'spur' on the top layer.  I can reposition it, in that general area, and I suppose I could edit the footprint to make the connecting trace shorter.

Is there a better approach?
If not, is there a way to make pad 3 a solid connection to the copper fill?

Thanks,

Andrew
 

Offline tox3

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  • Country: lv
Re: Net ties in internal layers - or alternative
« Reply #1 on: August 12, 2019, 06:16:56 am »
Not sure if i understand your question, but you could put Net Tie inside your ground polygon on Top layer to avoid spur.

And you can select pad and click 'E' to open pad properties, in Local Clearance and Settings tab you can change pad connection to solid.
 


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