Castellated / Half-Vias, parts 2 - 255

Thu, 04/22/2010 - 10:21am
Screaming Circuits

I've written about the Castellated / half-via mounting system a couple of times in the past. Now I can't seem to avoid them. I'm seeing them everywhere. The GPS I recently wrote about, low noise amplifiers, POL power modules, frequency synthesizers, VCOs...

When did this become the package of the day? I haven't even seen what IPC has to say about it yet but these things are all over the place. Our engineers and assembly folks are cool with it. It's not that tough to build, fortunately. But, as I saw with the ublox part I wrote about, there are new design issues to contend with.

I can certainly see the advantages of the package. The half via can allow for a good solid fillet providing good mechanical connection. They're typically a pcb-type substrate so the coefficient of expansion and flex strengths should be similar to the underlying pcb. On the other hand, like with an LGA the low profile after soldering will tend to exacerbate and expansion or flex risks.

Duane Benson

Once in a dream

Far beyond these castellated walls...



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