Correct way to add power supply pins?

Schematic
1

I’ve seen several threads where folks have had a similar issue - but I just can’t get it to work.

I’m on v8.02.
I have an OPA1679 (U1) quad opamp and I have placed 3 units. I sort of got the supply pins to appear
through an awkward trial and error process to invoke ‘unit E’ but it seems to have worked.

Now I decided to add the 4th unit(D) of U1 but of course it tries to add another complete quad op-amp
ok, so the process is auto-incrementing which I understand. But… how do I get the 4th unit of U! to appear?

TIA

2

Expand the OPA1679 symbol and select the D unit. It should have the same reference designator as the other units.
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If you have other ICs that have higher reference numbers you might have to re-assign refrerence designators by opening the tool on the top icon bar.

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Also remember to select ‘Reset existing annotations’

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3

amazing - thanks for the quick reply. I would have never found this!

1 Like
4

If it’s just for a few units of a symbol, you can also change the RefDes manually, either in the properties box of a symbol, or with the u shortcut key. You can also change the “Unit” in the properties of a symbol.

5

thanks - it sort of works based on the above suggestions. Far from ideal but I guess its just something I’ll have to put up with.

6

Why do you write:

There are multiple ways to do this quickly and efficiently, but KiCad can not (and does not try) to guess, so you will have to do it yourself.

7

It’s very simple:
place all five units on your schematic. Period.
You’ll have to deal with any unused units anyway (unconnected pins etc.), not only on the schematic (for ERC), but also later on in your PCB layout.
Buying 3/4 of a quad opamp is not an option.

3 Likes
8

Indeed, that is one of the simplest solutions.

Even when you do not use all of the opamp in a quad package. You should never just let the unused opamps “open”. Often the datasheet has guidelines on how to passivate such an unused opamp to prevent it from oscillating or doing other weird stuff.

I normally use the area outside of the “paper size” as a scratchpad to (temporarily) store all kind of things.

Manual renumbering (Either RefDes or Unit or both) is the second best option.

1 Like
9

This is a new one to me. Are you in the margins of the sheet (outside the ruler lines) or completely outside?

1 Like
10

Yes, of course. I don’t show that mess to others :slight_smile:

I put it completely outside of the “paper area”. I use it as a generic clipboard. Circuit snippets, text notes, “to do list”, rows of labels for a databus. A power supply section that still needs to find a place on the schematic. All kinds of things that may or may not part of the schematic, and are “loose ends” during editing. It’s a perfect place to park a few unused Units until you are ready for “that other part” of the schematic.

You can put plenty of space between such blocks, so they are easy to select in a single rectangle. But a small word of caution. KiCad does not like it much if you go further away then about 2 times the paper size. Beyond that zooming becomes a little bit awkward, but I have never had so many snippets anyway.

And then, when a project is around 80% done I usually do a cleanup and delete all the stuff outside the paper area.

11

i do that a bunch, and i used to feel guilty about it. glad to know other do it too! :rofl:

12

Valuable tip.
Thanks!