Hey guys, I’m getting close to sending off files to JLCPCB for my first try at designing a pcb. It’s a buffered/passive multiple, two pcbs will stack behind the panel.
1/ should I move the pcbs together and do a perforation I can break later to separate? Or separate the project into two files and order a set of each?
2/ for +12 and -12 I used 1mm trace width and for everything else I used 0.75mm. Ground net is in copper pour. Is this adequate? I don’t know the science behind it but looking at some mfos pcbs I have seems to be about that thick
3/ any other mistakes a first timer might make?
Thanks guys!
Btw I watched and followed along with the digi-key kicad tutorial series on YouTube
I think it’s mostly cost neutral (they charge more for multiple designs in a single PCB), but it doesn’t really matter, so you can just play around a bit in the ordering tool. Separate PCBs tend to look slightly better.
1 mm is good for a couple of amperes, so more than enough. You have plenty of space, though, so no need to change anything here.
See below.
Here’s some random comments/tips/nits/opinions, off the top of my head. Feel free to ignore some or all of them; it’s your PCB after all
Double-check hole sizes, footprints, and that nets makes sense (not sure what tool you’re using, but many tools show you the net name for each hole if you zoom in enough).
What’s up with all the electrolytics? I’d expect one 10 µF or so per rail close to the power connector, but what are the other two?
The ceramics placement also looks a bit arbitrary – decoupling capacitors should be placed close to the chips’ power pins (“as close as possible” but you don’t have to overdo it).
On the other hand, if any of these are part of a signal path, consider using the footprint for a polyester capacitor; you can still use a ceramic when building, but if you decide to go fancy, putting a narrow component in a slightly wider footprint is easier than the other way around.
Consider spelling out what the trimmers/connectors are for in the silkscreen, so you don’t have to remember what’s what when trimming/hooking things up.
Clearly mark the + and − sides of the power connector in the silkscreen, to make sure there’s no chance for confusion when building and plugging things in.
Consider using component values in the silkscreen instead of component numbers, to save time when building. That’s very much a personal preference, though, so feel free to ignore this.
If using component numbers, consider keeping them outside the footprint, so you can still read them once built.
Are the missing mounting holes in the component PCB a rendering issue, or are they actually missing?
That said, my #1 advice for PCB design is to keep in mind that there will be some silly mistake in this one. Or if not, in your next one
I hardly know what I’m doing either, but lately I’ve been using 0.75 mm for power buses and 0.25 mm for everything else, which is for instance roughly what I see in the Music Thing Modular Turing Machine PCB.
Fredrik thank you for taking the time writing those tips. I will definitely be implementing the changes, starting with the stuff I understand.
As far as the electrolytics, it’s probably cause I simply doubled a schematic and doubled up things unnecessarily. that being said the schematic has polarized capacitors called out at really small values:
I know the resistors aren’t typical values and I’ve swapped to closest substitutes. I guess I should probably take time to test the circuit on breadboard now that I think about it cause I’ve made a few changes and I really don’t know what I’m doing in this regard
The missing mounting holes are some graphical error cause they show up when I upload a Gerber to one of the pcb houses.
Definitely going to take the time to do the silkscreen changes.
Those capacitors aren’t polarized. Sometimes people use a -|(- for polarized and -||- for unpolarized, but in this case it’s -+|(- for polarized and -|(- for unpolarized.
In particular the 0.1µF caps between V- and ground or V+ and ground are bypass caps, you can use ceramics and they should go close to the ICs.
Was intending to have blues as the inputs for each buffered mult. Got the arrangement flipped so the red jack is the input on the right side. I could fix it by running wire instead of connectors but will probably just adjust my faceplate layout and deal with it.
Gotta say, going thru and learning the kicad process is rewarding, nice having the time to learn something new. Now Im ready for more, probably going to ‘PCBify’ this switch mult for some more practice.
. its really just fluff. any functions impacted?