AFAIK, multi-layer capacitors are supposed to be soldered with their multilayered plates parallel with the PCB.
Now, some MLCCs happens to have a square shape section (capacitor's height = capacitor's width), which makes them difficult to identify which are the up and down faces of the capacitor, and which are the lateral faces. For automated assembly, nobody cares about identifying which side should face the PCB, because usually the PnP machine will pick the capacitor straight from the reel.
For manual assembly of capacitors with a square section, identifying the correct side that should face the PCB is not possible without a microscope.
How bad would it be if a MLCC is soldered by mistake at 90 degrees (flipped 90 degrees along the capacitor's axis, not thumbstone flipped)?
I couldn't find any assembly guidelines talking about "sideways" mounting. Anybody know any guidelines about this, please?
Oct 21.2019, 17:44:07
For any normal application: It doesn't really matter.
As it happens, there's an app note out there (quick google didn't find it) showing that it does matter for RF applications, and that some RF caps are actually meant to be mounted with the plates vertical - and they're packaged in the tape that way.