Sanity check on footprint (resolved)

I hereby certify that I am not simply asking someone else to design a footprint for me.

This is an auto-generated message that is in place on the “footprints” section of the KiCad.info forum. If I remove it and ask for a footprint to be designed anyway, I understand that I will be subject to forum members telling me to go design my own footprint or referring me to a 3rd party footprint site.



Hopefully this thread doesn’t get deleted…

I just want to double check that the indicated footprint does match the datasheet indicated (full link: https://media.digikey.com/pdf/Data%20Sheets/Bourns%20PDFs/CAY17_Model_DS.pdf )

The footprint doesn’t match the component.
There are some serious problems with dimensions somewhere.

The “P” dimension in the product data sheet has 0.64mm or 0.126 mils. This is not correct.
0.126 mils = 3.2 mm and .64 mm = .025 mils. You will need to find other data sheets to confirm “P”.

Also, with respect to the Kicad footprint shown, the distance “P” is 0.052 mil or 1.32 mm, which doesn’t match either the metric or imperial measurement shown in the “product dimension”.

I didn’t bother checking anything else.

Be also careful with the symbol and the pins. In the datasheet pins 5 and 6 are “common” and the part is symmetric so that it can be rotated 180 degrees without problems. But in your symbol pins 5 and 10 are common, and the footprint is wired so that the part can’t be rotated. This design can’t work even if the dimensions were accurate.

EDIT: OK, you seem to have translated the pin numbers so that the symbol and the footprint match, although they don’t match with the datasheet. The “common” pin 5 goes to +5V. That’s probably OK, but I still recommend creating a symbol and footprint which match the datasheet.

The datasheet is indeed mysterious. In the KiCad library R_Array_Convex_5x0603 seems to be a closer match, it might work out of the box. The datasheet tells this should be 1206 size and “A = Common from terminal 5 to 10”. You should have a physical example in your hands and measure both the dimensions and the electric connections.

Good thing I decided to ask. Thank you.

EDIT: I went to Ultra Librarian LIKE I SHOULD HAVE and fetched the correct footprint, then realized the part was too small for me - went and found a more common SIP - AND fetched the footprint for that one as well. Looks like I’ve got some re-layout work ahead of me tonight!

(at least it was corrected before parts / PCB were ordered!)

So I spec’d out a different resistor network - CTS 746 series (the other one just wasn’t going to work), but now I have a different issue.

KiCAD is now complaining about clearance violations - saying the spacing is less than allowable (7.2 versus whatever the default is).

Now what?

Reset the clearances. Some, maybe most, footprints are script generated. They should always be verified and then saved off to a personal library for future use. Those clearance lines are overlapping the pads. The pads on the footprint should be verified as correct. If they are, the clearance is wrong.

A quick check of the board house’s spec and settings tweak was all that was needed. Thank you!

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