Wednesday, July 10, 2013

Don’t copy– Okay, don’t mind if I do?

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Nordic says don’t copy or use the EK and DK schematics as a reference . They say use the specific reference schematics and layout but design the antenna yourself. I don’t like that their Balun’s are different on the reference. I might ask why.
Sorry guys, but advice not taken. I’ve seen these work, with good range. The DK and EK trace antennas look to be identically built on 1.6mm FR4 boards with the same copper weight. The DK is two layer, the EK is four layer, but the antennas and components are identical. So I’ll try it.
ST Micro offered some help because of my twitter comment. After describing my problems they (correctly) blamed my reflow setup / stencil. I didn’t suspect it was a problem with their hardware, I suspect their Balun was meant for more professional production and that everyone, even the pros, will have to waste a few of these Baluns. Just less than me.  I just bit off too many things in one step. Namely trying to make an antenna setup while trying to get the ADS1248 onboard too and figuring out how to reflow a QFN. Baby steps people!
I might be able to shrink the size of the board back as the discreet balun moves the antenna up. This is good news as an L shaped board added 4mm to one dimension. This brings it back to near SD card sized I hope. 2 boards = 30 dollars, 4 = 50 dollars, and 30 dollars shipping. APcircuits turn around is hugely fast, so that’s who I’ll be going with on this. I’ll use OSHpark when I sort out any problems.

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