We have some amazing stuff in the pipeline (for registered beta users only - so join our open beta already, ok?) - announcement coming in a few days. But in the meantime, I thought it'd be useful to kick off an unofficial series of posts that might be titled "What To Avoid".
Since we we've started the PCB:NG Beta, we've seen a lot of different components being used in various designs. Now, some parts are easy to work with, some a bit more difficult, but there's one type of part that always fills us with dread: the Hybrid. Here's a great example:
Is it through-hole? Is it surface mount? Neither fish nor fowl it be - that there's a Hybrid. Yarrg.
The problem with hybrids is that they require hybrid manufacturing. Which means that, for just one part, you're going to need to have (and pay for) a second manufacturing process. In the USB-C example, above, here's the suggested land pattern:
You'll note that the suggested layout uses some small through-holes, with pretty thin annular rings. Now, I could get into painfully boring details about solder paste, reflow, stencils, selective soldering, apertures, paste release, etc. But instead, I'm going to say avoid these parts if you can. I mean, if you're not using old-skool through-hole resistors, caps, etc., why ruin things now?
One more thing - pretty much every EDA package out there will not, by default, include through-hole pads in your paste layer. Yes, your software is essentially telling you not to do it. Shun the hybrids. Shun them, I say.
But, aside from making an assembler's day just a bit less fun, why avoid these parts? Because, unless you're making a lot of units using this part, it's going to cost you - either in terms of straight-up ducats, or in delays and yield. Not a great outcome, especially if you picked a hybrid because it was a few cents cheaper, or it came up first in some web page.
So yeah, there's probably a nice non-hybrid (or less hybrid-y) equivalent. Like, for example:
Which has a much more SMT friendly land pattern:
But wait - isn't that a hybrid, too? Well, it is, but only in the sense that it has some retention elements that could benefit from solder paste. But things would work just as well if we didn't solder those, and used some adhesive to keep things in place. Better yet, those long slots are compatible with at least some surface mount processes - like PCB:NG's - and because they're not carrying signal, it's easy to modify things like we suggest here. To be clear: not all assemblers can shoehorn hybrids of any flavor into a pure SMT process. But we can, and do.
So, avoid those hybrid-y hybrids where possible, and go make something amazing.
Update: folks have asked me to more clearly define what a hybrid is. So, if a component uses both SMT pads, and through-hole pins for anything beyond structural purposes (i.e., signal, ground, etc.), it's a you-should-shun-it-hybrid. And you should.