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I'm trying to create a footprint for the ACS770 current sensor in Altium Designer (17.1), which has a quite irregular shaped pad: ('round' pad shape with slot hole, and then a small cutoff in the middle). How do I generate such a pad shape?

This is what it should become: (Datasheet)

Datasheet layout

This is how far I get in Altium:

Altium result

The vias are no problem, but I don't know how to create the 1 mm 'cut-off-space' between the two pads.

Everything I can find on custom pad shapes for Altium is with SMD pads, in which case you can just draw a small pad, then extend the surfaces using regions or other primitives, but no results for through hole / multilayer pads...

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3 Answers 3

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Figured it out!

You can do the same trick as with the SMT pads, but draw on the 'multilayer' layer.

Steps:

first steps

1) Draw Small pad with correct slotted hole 2) Draw half a circle (on the left of the left pad) on the 'Multilayer'-layer. Set soldermask / paste expansion to 'from rules'. 3) Draw the cutoff circle on the right (using circles and lines). Use Tools --> Convert--> Create Region from selected primitives to get the shape in the center of the pads, set the soldermask / paste expansion to 'from rules' for this region.

Result: result

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  • \$\begingroup\$ You will actually find official tutorials on Altium custom pad shapes if you look. Usually something like this doesn't have to be asymmetric on every layer so you just need bespoke copper on the surface layer(s), but given the hole is ringed with vias, what you did seems the best option. \$\endgroup\$
    – Barleyman
    Commented Jul 16, 2019 at 10:02
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Make the slotted pads smaller, and create copper regions as in this answer by using convert from primitives.

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  • \$\begingroup\$ Thanks! The clue for me was that you can actually draw on the 'multilayer'-layer! \$\endgroup\$
    – Arjo van der Ham
    Commented Aug 28, 2018 at 19:29
  • \$\begingroup\$ Feel free to select your own answer, it looks more helpful. \$\endgroup\$
    – Spehro 'speff' Pefhany
    Commented Aug 28, 2018 at 19:41
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Thank you for the tip! I uploaded this to SNAPEDA so I could post the link to this part (ACS772 from Allegro) and there was already a footprint on there!

Here is the link in case someone wants it:

https://www.snapeda.com/parts/ACS772LCB-100U-PFF-T/Allegro%20MicroSystems%20LLC/view-part/?ref=search&t=acs772

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