macegr wrote:They're actually forked (bifurcated) and soldered on both sides of the PCB. In the tens of thousands of modules using these pins we ship every year, none have ever come back with a pin ripped off the PCB. That's because these devices are pushed and pulled vertically in sockets or breadboards, side or twisting forces are just not going to happen.
The pins are fragile enough to break after a couple of bending cycles, but in that there is no difference from normal DIP leads.
It saves a bit of space (especially with more than 2 layers) and some FR4, and won't destroy an IC socket like normal square pins would.
Ah - I didn't realize they were soldered to both sides. So that means you have to be sure to get the right size pin for your thickness of PCB. It does however mean that they'll have some strength - still a fraction of that that you'd get with a through hole pin, however.
I wonder how these are soldered in production environments... They can't be pick and placed - and they have to be soldered in with a jig of some sort to ensure proper pin spacing. Maybe there's some specialized tooling for them? I'd be really interested to hear.
As far as I can tell they actually use more board real estate than a through hole pin (the SMT pads are as big as a through hole pad and then they take up space on the side of the board where the actual pin sits) and force you to put them on the edge of the PCB - but the savings I suppose come from when you want to run tracks on the inner layers. I don't buy that they protect IC sockets as you can get pin headers with any size pins and even round pins.
I'm still having a lot of trouble figuring out why anybody would design these things in to a product. Seems like they add cost, reduce options, reduce strength, and make assembly more difficult. I supposed if you need the connectors to have a specific pitch, they allow you to make the PCB slightly smaller. But that's all I can really think of...