“Rev 1” Xmega adapter art


I’d mentioned a post or so back that I found assembly costs to suffer from the use of QFN chips, and that I was going to redesign the Xmega adapters to use PQFP instead.  Here they are:

I call these the “rev1” boards because the first round of QFN’s were the real functional test.  These boards have identical schematics, just different parts implementing it.  The pins are now surface-mount on the bottom of the board, which doesn’t even come close to offsetting the costs of the QFN when it comes to assembly (quoted at Screaming Circuits).  I’ve also switched the A3 boards back to 0603 caps, since while I can do 0402’s by hand (the first rev0 A3 board is assembled and working as well!), I don’t think they’re going to scale well for production.  They spend half their time stuck to the tools instead of the board…

I’m going to turn a set of 3 of each of these with the next group order to make sure I can do the bottom-side headers, then these will be the “final product” boards until something else needs to change…



  1. Does a hobbyist have any hope of soldering surfacemount header pins by hand or do you pretty much need professional assembly to do them? I’ve never seen them before..

    • That’s what I’ll be finding out next week ;-). My plan is to put the pins either in a socket or through a pcb to hold them, paste the bottom of the board, then hand-tack the corners. Flip it over and place the the components, then toast (sorry, “reflow”) the whole jig.

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