I'm trying to wrap up a PCB layout for a client who insists the DRC should have no errors or warnings, however irrelevant they are. All is fine except for 1 last warning and I can't find the source of it, see screenshot of dialog:



I get what the warning is telling me - I just can't find where it thinks an SMD part expects 'Through hole' pads. The part in question is the TI 74HC4067 which is in the KiCAD library with both SOIC-24 and TSSOP-24 footprints. However I'm using the VQFN-24_EP2 variant of the chip which isn't in the library. So I modified the symbol to add the 25th 'pin' for the thermal pad, changed the part # to add the RGYR (VQFN package) suffix and added the part to my project library and then assigned the TI RGYR VQFN24_EP2 footprint from the footprint library to the part. All was well til I ran the DRC and this violation pops up! I can't find anywhere any reference to through hole pads, everywhere I've looked says SMD. What am I missing? Its seriously doing my head in... and I need to get this out of the door like yesterday1

 

Should that be designated HTSSOP ?

 

Should that be designated HTSSOP ?

I don't think so. This part doesn't come in an HTSSOP package, TI very definitely call it VQFN-24

 

https://gitlab.com/kicad/libraries/kicad-footprints/-/work_items/2634

The thermal vias (they're actually pads) need to have the "Heatsink pad" Fabrication property on them.

Maybe try that if you haven't already.

 

https://gitlab.com/kicad/libraries/kicad-footprints/-/work_items/2634

Maybe try that if you haven't already.

Thanks, I'll give it a go, though I tried removing the vias earlier, sort of thinking along those lines, but it didn't change anything.

 

https://gitlab.com/kicad/libraries/kicad-footprints/-/work_items/2634

Maybe try that if you haven't already.

Yep, that worked, eventually. Took a couple of goes to make it 'stick', don't know why, but all good now.

Many thanks!

[edit] I note on the changelog for 9.0.0:
"@kliment @kliment1 10 months ago
Owner

We have since regenerated all affected parts so this should no longer be a problem. Closing it for now, but please reopen if you find any we missed."

Clearly this was missed!

 

You may have duplicate pin numbers or hidden pin conflicts. Please check using the Update PCB from schematic tool.

 

You may have duplicate pin numbers or hidden pin conflicts. Please check using the Update PCB from schematic tool.

Nope, nothing like that, it was exawctly7 as stated, the heatsink vias were not classed as 'heatsink pads' so forced the whole part to be 'through hole' despite being designated an SMD footprint. I just managed to find the one(?) footprint that hadn't been regenerated properly in the move to v9.0.0! I am very familiar with 'Update PCB from schematic' and that wasn't resolving the issue, nor would it until the base footprint was fixed.