topic Re: Conventional symbol for dual op-amp power pins. in EAGLE Forum

Conventional symbol for dual op-amp power pins.

Anonymous — Thu, 08 Aug 2019 12:50:40 GMT

Hello,

I'm just getting into EAGLE and loving it so far. I have a question about circuit schematic conventions as they relate to the EAGLE schematic editor that I can't seem to find an answer to.

I've placed some dual op-amps and I want to specify the power pin connections so I've added them to the schematic using invoke, so far so good. You can just place these extra pins over the op-amp symbol to show it in the conventional fashion but I can only seem to get one set of these pins so can't do this for both symbols in the package. It strikes me that it would reduce clutter to show these pins separately anyway but I'm not sure if a circuit diagram convention exists to label these pins as belonging to the package in question. Could anybody kindly shed some light on this situation?

Thank you.

Re: Conventional symbol for dual op-amp power pins.

trey — Thu, 08 Aug 2019 13:13:39 GMT

I would say this is your schematic so you can do it how it looks best to you. Personally to minimize clutter and group decoupling capacitors with the power pins, I place the power pins away from the actual opamp symbols. Something like this:

If I were to have the power pins on the triangle opamp symbol it would clutter up the area where the feedback path is normally drawn. Hope this helps.

Re: Conventional symbol for dual op-amp power pins.

Anonymous — Thu, 08 Aug 2019 14:14:45 GMT

Thanks very much. That is more or less how I've got it.

How did you get the name of the component on the power pins?

Re: Conventional symbol for dual op-amp power pins.

trey — Thu, 08 Aug 2019 14:27:25 GMT

Open the power symbol in your library. Make sure there is a text object on the names layer with the text ">NAME". You can do the same thing on the values layer with ">VALUE" (both without the quotes).

Re: Conventional symbol for dual op-amp power pins.

Anonymous — Thu, 08 Aug 2019 15:36:34 GMT

Oh okay, thank you.

So I guess it's best to create a custom library for each project and copy all the parts over, rather than working directly from the managed libraries.

Re: Conventional symbol for dual op-amp power pins.

trey — Thu, 08 Aug 2019 15:56:33 GMT

It's up to you. I use some of the built in library parts occasionally. Much more often though I will copy a known good footprint from one of the built in libraries and make my own symbol and device for it.

I'm surprised the built in libraries don't have the name tag on the power pins. Maybe you could try using the reposition attributes tool on the power pins in question. Sometimes this will cause the reference designator to show up if it isn't.

Re: Conventional symbol for dual op-amp power pins.

Anonymous — Thu, 08 Aug 2019 16:22:44 GMT

Yeah, that's exactly what confused me, I thought I was missing something. Once you swap in the adjusted symbols however, you can use the reposition attributes tool to get the new label to appear.

Thanks for the tip about the footprints, I will make use of that when I swap in the final components.