Try Tools > Edit Symbol Fields
Not necessarily. If the footprint has the same pin number for multiple pins, it means they are already connected inside the part. It needs a datasheet check to see the routing recommendations.
If two pads have the same number, the layout editor will require them to be connected, regardless of what the internal situation is. If you wanted latitude in whether they are connected on the PCB or not, then a footprint with distinct pad numbers should have been chosen.
Thank you! I know those might seem obvious choices, but I’m still trying to take it all in. I learned basic electronics as a teen, but there’s a lot I did not learn and, often, part of the issue is that often one does not know just how much is out there that they don’t know!
This helps me in several ways. I was thinking there might be a classification system for types or shapes of components, but the idea was vague enough in my head I wasn’t yet sure just how to ask about it. I searched for SOT223 and that led me, in a few steps, to searching for “electronic package types.” From there, with a bit more searching, I found TO-220 as a package type image that matches the package for my +5V voltage regulator (LD1117, +3.3V). From there I checked in the Footprint Chooser and found that I can search on package types.
So that’s a big help. I was overwhelmed by trying to sort through so much information and didn’t want to just ask, “What package works for this component?” because I wanted to learn what to do to find that on my own. I guess I could have just asked it that way, but now I see a bigger view and can do this with other components, too.
@retiredfeline You mean, if one pad is connected, the rats nest line still stays with the other pad?
Interesting.
I haven’t been in that situation myself, but it seems to limit the layout options somewhat.
Symbol is three-pin, but package is four-pin due to the leadframe layout. Don’t see how that can be solved easily.
Try it yourself.
There are symbols and footprints to accommodate all permutations.
Related follow-up to this question:
This project is for a control panel. I know project packaging is often designed so switches and LEDs can be mounted directly on the PCB so when it’s all put together, those components will fit into the plastic package. I want to do that with some components, for practice. Others, for instance, I will be using some LEDs and I think I’m going to just have to solder wires to them and use molex pins and plugs to connect them to the circuit board.
I want to make sure I understand the process for handling footprints in this kind of situation.
Since I’m going to use an LED, but not mount it right on the PCB, I can choose a footprint for two molex pins on the board (instead of an LED) and that will work for just this project. Then, on other projects, I can still use anu default or otherwise matching footprints.
Do I have that right? So I can use custom footprints for any component for a single project whenever needed?
Yes, that’s a common strategy.
I want to add that my issues are resolved now. I may have to re-choose some footprints because of sizing or similar issues, even though I’ve checked things out carefully by looking over dimensions and other data. On this first project, I have run into 2 issues. One is that I have to create a footprint for my USB-C connector, which only has 4 pins on the circuit board (GND, Vcc, D+, and D-). I’m using that kind of connector because there are a number of projects I have planned that will use a USB connection for power and won’t be communicating with anything. I was hoping I wouldn’t have to dig into footprint design until at least a few projects were under my belt, but I guess I just need to dive right in.
Thank you, everyone, for all the help!
2 Likes
A very common method to create a new work of art (footprint) is to start with something similar and modify.
In your case, open the “Connector_USB” library and go surfing. At least one of the Kicad symbols will be similar.
Highlight the suitable footprint, right mouse click and “Save as” into a personal library. Now open that Personal Library file in your Footprint Editor and make the appropriate modifications, give it a name and save.
Once you are familiar with how the Schematic and Footprint editors work, usually a modification like this is under a 5 minute exercise.
And don’t forget my above comments: don’t be afraid to keep changing the grid to make pad and graphics placement easy. 