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I'm making LED light panel which will contain lots of high power Surface Mount LEDs connected in series. I'm using the LUMILEDS Luxeon Rebel Series LEDs which has three pads on each LED, an anode, a cathode and a thermal pad. Therefore, I would like to use an aluminium board so I can attach a heatsink to the panel.

My question is how can I use Eagle to design a board for aluminium boards where the thermal pads are connected to the aluminium board? Also, what files do I need to send the PCB manufacturer?

enter image description here

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    \$\begingroup\$ Find a manufacturer that does aluminum boards and read their guidelines? \$\endgroup\$ – Passerby Aug 28 '16 at 17:15
  • \$\begingroup\$ Isn't this just going to be a one-layer board on a special manufacturing process? There would definitely be something special if you wanted the thermal pad to be direct-attached (non-isolated) to the aluminum board, but I have no idea how that is specified. Definitely talk to the PCB fabricator(s). \$\endgroup\$ – user2943160 Aug 28 '16 at 17:18
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I found the datasheet for these particular LEDs here: http://www.lumileds.com/uploads/28/DS64-pdf

An Aluminium board consists of 3 layers. At the very bottom is the Aluminium, at the top you have the copper and separating the two is a thermally conductive dielectric layer. The dielectric layer is so good at conducting the heat to the Aluminium layer that you don't need to physically bond the thermal pad directly to the Aluminium.

Design your footprint (aka package) with 3 pins; an anode, a cathode and a thermal ground (or TG for short).

footrpint

Next design your schematic symbol with 3 pins; again an anode, a cathode and a TG. Finish off the connections of pad to pin in the Device section.

When you are creating the schematic, draw a net connected to the TG pin and give it a name.

For an Aluminium PCB you can only use a single layer. Hybrid (multilayer) boards are possible but I suspect you are after a plain Aluminium PCB.

When you lay out the PCB place the LED part into position. Now this on its own is probably enough to transfer the heat to the Aluminium.

However, I go that extra step and add a copper pour (aka plane/region) to the TG pad. To do this draw a polygon region that overlaps the TG pad. Then you must change the name of the polygon pour to that of the net that you connected to the TG pin in the schematic.

footprint with copper pour

You will need to generate the following gerbers using the CAM feature:

  • Board outline
  • Top copper
  • Top soldermask (aka tStop)
  • Top silkscreen (aka tPlace & tNames)

If you are getting a stencil you will also need to send the Top paste (aka tCream) gerber.

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Eagle has a guided tour on it´s website: https://cadsoft.io/tour/. Just watch the video "Producing CAM Data".

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    \$\begingroup\$ While this link may answer the question, it is better to include the essential parts of the answer here and provide the link for reference. Link-only answers can become invalid if the linked page changes. - From Review \$\endgroup\$ – Ricardo Sep 20 '16 at 12:53
  • \$\begingroup\$ @Ricardo While this is probably not the best answer, it is not a link only answer, and shouldn't be moderated. If you feel it doesn't answer the users question, feel free to down vote it. \$\endgroup\$ – Voltage Spike Sep 20 '16 at 15:13
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    \$\begingroup\$ With all due respect, @laptop2d, if this isn't a link only answer, I don't know what is. If you remove the webpage at the other end of the link, there's absolutely no information left in the answer. But definition, this is a link-only answer. Note that the comment I posted is a ready-made one, provided by the system, which explains precisely why link-only answers like this are frowned upon here. If you disagree, just flag my comment(s) for moderator attention. \$\endgroup\$ – Ricardo Sep 20 '16 at 15:25

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