Hi,
I'm trying to create a simple TQFN-16 breakout board.
I want to link the component's bottom pad to the bottom layer of the board with a couple of vias (to increase heat dissipation as per manufacturer's recommendation).
I have assigned the correct nets to all the parts, but the PCB editor is still showing a design error - the pad is not connected to GND.
Is this a simple design rule check error or would the pad really not be connected to the bottom layer?
The project is public if anyone is willing to have a look: https://easyeda.com/zoltan.markella/TQFN_16_breakout-2ce8a053f6a24ef688c2631f6e092c43
Thanks,
Zoltan
Hi Zoltan,
I'm not sure why your footprint gives this error but if you delete the net name
GND
in the centre pad (pin 17) and then check the Design Manager, you will find that theGND
Net error disappears.Even if you decide not to delete the net name, the vias will connect to the bottom layer OK. You can check this in the Gerbers.
16QFN3X3 w/ 0.3mm vias
to
16QFN3X3 with 0.3mm vias
because the
/
character is not allowed in schematic symbol and PCB package names. If you try to update the PCB, you'll find it throws aPackage Error
.If you change the name and update the package in the schematic and then do an
Update PCB
, you'll find the PCB updates with no error.BTW, I have tried creating your package with the vias already in it but for reasons I do not understand yet, it does not make a connection to the ground flood on the bottom layer.
I did create some pads that are on all layers and have vias through them which do connect to tracks and layers correctly. You could use them as the basis for a variant of your footprint but be aware that the pad on the bottom layer will connect to the bottom layer with heat shunt spokes.
6MMPAD
8MMPAD
10MMPAD
Lastly, since your PCB footprint does not actually have any vias in it and you have to add them once the footprint is placed in the PCB, you may want to rename the footprint to remove the
with 0.3mm vias
bit.:)