Copper pour in SMD footprint

[new2kicad]

I have a high power SMD LED that I am designing a footprint for. It has 2 pads either side of the LED, then the die in the centre itself needs a pad for thermal relief (the die is located where the “LED” text is below). Annoyingly the die’s pad is tied to the LED anode so I cannot use a normal layout editor copper pour. These are the pads:

Basically I want to do a copper pour within the courtyard that does not touch the pads. I don’t want to have to draw a polygon with pad-shaped cutouts in.

Is it possible to do a copper pour in the footprint editor?

BTW the footprint is 20x20mm.

Is there some alternative like I create a 3rd pad which I can manually copper pour later in layout editor? I’d appreciate any ideas. Thanks.

[mf_ibfeew]

Basically I want to do a copper pour within the courtyard that does not touch the pads. I don’t want to have to draw a polygon with pad-shaped cutouts in. Is it possible to do a copper pour in the footprint editor?

No, copper pour (zone fills) is not available in footprints. Some time ago there was a issue regarding this topic on gitlab (Feature Request: Allow filled zones to be defined in footprint (#10738) · Issues · KiCad / KiCad Source Code / kicad · GitLab), but there are usability-concerns (to which net should the zone connect? How to define that at FP-editor design-time?) as well as implementation difficulties.

I don’t want to have to draw a polygon with pad-shaped cutouts in.

Unfortunately thats the way you have to go.

Additional thought: you wrote "the die’s pad is tied to the LED anode " - so the polygon could have a connection to Pad2 - hence a simple rectangle is enough (avoiding the complete left side with the Pad1-GND-cathode Pad).

[new2kicad]

Okay, thanks for clarifying this.

The datasheet recommended footprint has the +ve pad not connected to the die copper pour which is strange:

That said it is probably easiest to do a polygon connected to the positive pad like you said.

[JeffYoung]

I think you’re misreading the (somewhat crappy) datasheet. I don’t think the middle arrow attached to the “Copper” callout is pointing to the diagonally-hatched area, but rather to the 6mm circle in the middle.

I’m not sure what the diagonally-hatched area is suggesting, though, and a larger thermal pad would certainly make sense.

[eelik]

I agree: the arrow seems to point to the circle which has similar texture than the two other pads. I interpret the hatched area as a continuous copper fill but covered with mask. It’s connected to the circular pad. It’s only a suggestion; in reality you want as large continuous copper area as possible. The idea is of course transferring heat as much as possible. You should just add a large zone around the circular pad (in the PCB layout), with “solid” connection without thermal spokes.

[Fabio_De_Bernardi]

@new2kicad

That said it is probably easiest to do a polygon connected to the positive pad like you said.

I understand that a PCB with high heat dissipation is needed.
Aluminum PCB?

[new2kicad]

Yes, I am very excited about doing my first JLCPCB single layer Al board with white silkscreen!