Products such as the RN-41 Bluetooth module are SMD PCBs with pads that cover a surface layer and the side of the PCB; sort of like a via that has been placed to overhang the edge of the PCB.
How do I create pads like this with Eagle CAD?
Just to be clear: I want to make pads like those seen on the RN-41. I do not want to make pads that the RN-41 would be mounted on.
Put the pads at the edge of the board, and have the board routed across them.
I don’t understand what you mean by: “…have the board routed across them.”
I need to create the pads in CAD so that my manufacturers create the correct PCB.
Have the board cut across the pads by routing. Other cutting methods might not produce a cut that is clean enough.
Sorry, I’m not sure I follow. I think you are saying to have parts of the pad exceed the board dimensions in the CAD. This will only result in copper up to the edge on a given layer. I need the side of the PCB to be plated as I described in the original post.
I don’t see the problem. The board is simply routed with a cut through the pads and holes.
It’s a non-standard process as the board is being cut inside the outline, so you have to request it.
Those pads are called “castellations”. You may want to contact the board house and ask them how they prefer them done (and if their process can handle them)
/mike
n1ist:
Those pads are called “castellations”.
Thanks for the keyword. A Google image search for “PCB castellations” returns some screen shots of EAGLE cad with vias/through-holes placed so that half exceeds the board edge. I think this may be the solution.
Sorry, leon_heller. I now see this is what you meant. I was taking you too literally and could not see how a “pad” was going to solve my problem; I interpret a pad as being on a single layer of copper appose to a via or through-hole that is plated through all layers. Thanks for the answer.
I’ve created the package as an array of vias with defined diameter and drill value. The problem is that Eagle (5.1, freeware) will force the drill value to be ‘auto’ when the part appears in a board. This will result in a very small plated surface on the castellations.
Does anyone know how I can have a drill value defined in a package not be overridden to ‘auto’ once it appears within the board?