Name for components that are not mounted?

Hi,

I've always been wondering if there's a word for components on a PCB that are not mounted on purpose. For example, I often add footprints for capacitors in op-amp designs, just in case i'll need them if the thing oscillates. In the schematic I typically use the symbol of a crossed-out capacitor. Same for resistors. I saw this practice in quite a few other designs, and I think some of you did too.

Since I'm not a native English speaker, I wonder if those have a name? In German some people jokingly call them "anxiety resistors/capacitors", because one is anxious that the design might not work without them.

I read the term "depop" in reference schematics from Hittite, but a few minutes of googling tells me that this doesn't seem to be a wide-spread term. Except for depop circuitry in audio applications, which is a completely different thing.


Best regards,
GooGooCluster

Optional? Discretionary? I can't say for sure, having no experience at professional manufacturing.

Usual component specifiers are n.m. (not mounted) or n.p. (not populated/placed). In this case, special place holder component may be used in CAD designs. Most tools support also design variants, you can define a "lab" and a "production" variant with and without these optional components.

In case of the series damping ("anxiety") resistors, a zero ohm jumper must be placed instead, omitting/crossing out won't work.

Hi,

thanks a lot!

With "anxiety resistors" I actually had other conditions in mind than damping, the capacitors on op-amps were just an example, sorry for the confusion. I really wanted to refer to situation where crossing out is the only choice, and that question is answered


Best regards,
GooGooCluster

There are circuits designed for multipurpose applications, so you will find in some cases a whole region of the board without components, as for example if for a specific project do not need some kind of communication, some sensor, etc...

In most companies (in the US) that I've worked for label parts as DNI (Do Not Install) if they aren't to be placed. If there are variations of components used depending on some feature or part being on the board then there is usually a table that shows which parts are DNI or not.

the depop you saw stood for depopulate in the Hittite schematic.