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When choosing how to lay out footprints during packing, does KiCad take into account electrical connections between them?

(This does sound like an extremely useful feature either way, but I'm curious.)



It appears to now, yes. It didn't before. One of the bigger headaches (for me, as a beginner) was when you had bypass capacitors that need to be physically as close to an IC as possible. However, the two pins go to a voltage source and ground. According to Kicad, those could be placed anywhere on the board, and have no direct relation to the IC itself. This meant you had to carefully find each capacitor by its reference and move it to where it needed to be - often it was packed somewhere completely irrelevant. Now it appears to be much simpler since you can select the components from the schematic and pack them together in the PCB editor, saving a lot of time.


Trick is to print the schematic out, draw red circle around each "decoupling environment" and then group them on the board like that. Then place the connectors where the mechanical design demands them and move the groups where they need to go. Then do the signal paths, then the power routing, then the ground fill.

Kicad doesn't make that particularly easy but one of the big errors people make is at schematic capture stage where people chuck all the decoupling capacitors in their own sheet or separate net all across the power bus. They belong next to the devices you are decoupling on the schematic.

Canonical good example from the HP 3478A service manual: https://imgur.com/LQiAKtI


I am a total amateur here. But I found it natural to keep a relative spacial coherence in the schematic, and have it somewhat similar on the PCB side.

Though kicad would just dump everything randomly when moving to thr PCB view. As I understand, "packing" should help keeping this spacial grouping.

There is a plugin though[1] that does place the components on the PCB similar as they are placed on the schematic (and this does work with sub-sheet too). This is tremendously helpful starting point.

[1] https://github.com/ian-ross/kicad-plugins


Isn't C312 the wrong way around?


The curve doesn't imply polarization; see C306 on the right.

(I miss resistors that go -v^v^v^-. Why would you use a box? Boxes are for black-box ICs.)


Ah, right. I'm used to caps being 2 flat lines for unpolarised.


In 6 you can select the bypass cap in the schematic editor and that will highlight it in the PCB editor but only one at a time. Still better than searching for C18 though.


> This meant you had to carefully find each capacitor by its reference and move it to where it needed to be - often it was packed somewhere completely irrelevant.

1. Draw bypass caps for every IC as its separate space on schematic (also declutters the schematics that way)

2. Group them together on PCB then just... drag one (or two if you have say 100n + 1n) each to each IC.

Alternative is 0 ohm resistor (net tie footprint) before every power line so the cap and IC are on separate netlit


I concur. This is a limitation of the net model. I've found the net model works well for most cases, with this as a notable exception.

Maybe the play would be a special BP cap setting on the schematic, that binds to a specific part + pin.




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