PCB Edge USB C Connector Library

https://github.com/AnasMalas/pcb-edge-usb-c

by walterbell • 9 months ago

170 92 9 months ago

15155• 9 months ago

What PCB thickness is optimal? The USB-C tongue on a shieldless part I use is ~0.7mm, which is a pretty thin PCB.

webdevver• 9 months ago

i wonder how often you can plug/replug the connector in this case. how will the pcb material hold up? with my press-fit or clip-fit (is that a term?) 3d prints, ive noticed that 20 cycles can be sufficient to induce substantial 'loosening'.

ggm-at-algebras• 9 months ago

Plug an OTG cable in and connect to that, so you don't repeat plug-unplug?

Kirby64• 9 months ago

It’s likely in the order of 10-30, especially with something like ENIG as a finish. If you wanted more cycles, you’d want to switch to a hard gold finish which would likely increase the cost substantially.

This is truly only for a debug port, not anything else.

AnasMalas4• 9 months ago

I have posted new test results on the github! It did 110 mating cycles without any major issues

Taniwha2• 9 months ago

They say "use 0.6 mmm"

https://x.com/AnasYMalas/status/1982060711670067350

Taniwha2• 9 months ago

+copper+ENIG is going to make that 0.7mm

peteforde5• 9 months ago

That is a very thin PCB. For anyone reading this, 1.6mm is standard.

jmgao• 9 months ago

I've found 0.8mm to make much more reliable connections, since the specification says that the tongue should be 0.7mm. 0.6mm will disconnect if the cable is angled in any way.

peteforde5• 9 months ago

In a similar vein, I discovered and have started using the Tag-Connect TC2030-USB to program/troubleshoot my boards. While it's technically/originally intended as a way to do JTAG debugging, I am completely enamored with the ability to drop a footprint on my PCB and be able to connect to it without having to place a relatively expensive connector (or a connector at all) that I don't necessarily want users interacting with.

https://www.tag-connect.com/solutions-target-devices/usb-ser...

They have FTDI versions as well, for those who want the full USB boot/reset treatment.

Also, they have another connector for attaching to castellated edges. I think it's just so clever.

Brian_K_White2• 9 months ago

I just use ordinary straight pin headers and stagered via holes. The board just has vias and the cable just has a plain pin header not even pogo pins.

stavros4• 9 months ago

Why vias? So the pins don't go all the way through? Wouldn't any disparity in the lengths of the pins make that pin not touch?

wrs• 9 months ago

I've been doing a cheap DIY version of Tag-Connect for some STM32 projects (6-pin debug). I just put the holes for a pin header near the edge of the board, and use a pogo clip to connect [0]. (These are readily available on AliExpress in various sizes.)

[0] https://www.adafruit.com/product/5433

edanuff• 9 months ago

I do exactly the same on my boards and use that same clip.

jkestner• 9 months ago

Same, enamored and I’m not even the EE. Elegant, no cost on the product side, and I don’t have to take the board out of the case to access it.

exmadscientist11• 9 months ago

They're fine for one guy using them on the bench but they are a nightmare for mass production. The 50-mil pitch is annoying to make work with a bed-of-nails fixture, the clips are fundamentally incompatible with production lines, either robot or human, the parts are expensive, and the cycle life is not there.

I have had one too many arguments with firmware people who think these things are sufficient for production that I am just done with them by now. There are other ways to do it.

pidge• 9 months ago

Out of curiosity what are the other ways?

ACCount37• 9 months ago

This reads like a skill issue to me.

The only actual issue I had with Tag is that it takes up more space than an array of aggressively placed test points would. Which is still acceptable in some designs.

If you can't hit a massive, enormous 1.27mm pitch connector complete with dedicated indexing holes with your jig, I can't fathom how that would be the fault of the connector.

technothrasher• 9 months ago

We do smaller production runs of typically 100-1000 boards and have had good luck with the Tag connectors for programming them.

mmoskal• 9 months ago

I had good experience with carefully spaced holes in PCB and a 50 mil header, see https://jacdac.github.io/jacdac-docs/ddk/firmware/jac-connec...

amelius2• 9 months ago

You might be interested in this "SKEDD" connector:

https://www.we-online.com/katalog/media/o210254v410%20ANE011...

https://www.digikey.com/en/products/detail/w%C3%BCrth-elektr...

_Microft• 9 months ago

Maybe you like this - "paw connect", a whimsical version of the footprint for this connector:

https://github.com/LeoDJ/Paw-Connect

the__alchemist3• 9 months ago

I wish the cables weren't so expensive! They do wear out after a while; had one die that way. Using the 2030-NL STM32 6-pin one.

JKCalhoun2• 9 months ago

That's cool but I am not sure how a customer of mine would feel if I shipped a board to them like that. (I could see trying it on a project for myself, though.)

mananaysiempre4• 9 months ago

The problem with USB-C connectors for hobby projects is that they are ass to solder by hand—I’m still looking for one that would use a larger pitch by shorting the four USB pin pairs for either orientation. If you’re shipping something to a customer, I think it’s fair to assume that you don’t really have that problem :)

exmadscientist11• 9 months ago

Do you find the 6-pin charge-only Type-C connectors too small? Or the 16-pin 2.0-only ones? They seem reasonably hand-solder-friendly but I admit I've been fortunate enough to have the factory handling them for me.

murderfs2• 9 months ago

Get a hot air gun: it'll make your life way easier. You can tin the pads with a soldering iron, put the connector on and squirt some flux on the leads, and then just blow hot air until it reflows into place.

LiamPowell• 9 months ago

They're also ass to make PCBs for. The second you need 2oz or higher you start to really push the limits of what most prototype shops can do.

This is a pretty standard 2.0 receptacle, you've only got 0.2mm between pads if you follow their footprint (literally the limit for soldermask bridges on 2oz at JLCPCB): https://gct.co/download?type=PDFDrawing&name=USB4105.pdf

peterburkimsher• 9 months ago

If you're interested in other PCB edge connectors, here's an HDMI one I designed:

https://forum.kicad.info/t/hdmi-pcb-edge-connector-for-raspb...

geepytee• 9 months ago

Very clever packaging of a connector

izonu• 9 months ago

Here is a similar project in the sense that it uses no connectors on the PCBs, using a SOIC-8 clip to bite into the board. I think it's pretty clever.

https://github.com/SimonMerrett/SOICbite/

dvh• 9 months ago

Doesn't it require ENIG? I wanted edge connector for my pcb project but it adds $20 to the price of pcb, that's just too much. Anyone knows card edge alternative? I'm thinking pin header but that's not very user friendly. Edge card can be inserted blindly even if you don't see the connector, pin header would probably just bend irl.

the__alchemist3• 9 months ago

ENIG sounds expensive right? Double the cost of your board or w/e? IMO it's no big deal because::

  - A: If you want a 6 or more layer board at some places, you have to get ENIG anyway, and solving routing puzzles isn't my idea of fun.

  - B: The PCB price is a small portion of the overall price anyway; parts and SMT dominate. So you're paying 2x as much on 15% of the total or w/e.

sagarm• 9 months ago

Eh for a hobbyist it's simpler and more robust to just put a connector on the board or use a test clip. I use clips like these: https://www.aliexpress.com/item/1005007622121847.html

You can choose your spacing: 1, 1.5, 2, or 2.54mm.

mrheosuper• 9 months ago

the only people who gonna use this footprint is hobbists, and they care a lot about cost.

stavros4• 9 months ago

solving routing puzzles isn't my idea of fun.

This just illustrates how different people are: I sometimes make PCBs just to route them! It's by far the most fun part for me.

tuetuopay• 9 months ago

I've done HDMI edge connectors like this using plain HASL without too much trouble. Just don't forget to remove all soldermask on the connector path, they'll dirty out quickly otherwise.

But, now I do ENIG everywhere because it's often the same price as lead-free HASL (or so close it does not matter), while looking way cooler. I've started to take quite seriously leaded stuff now, especially since low temperature lead-free solder exists (SAC305).

Velocifyer• 9 months ago

I was looking for this for a while!

the__alchemist3• 9 months ago

This is very cool! What is the practical intent, given USB ports are 69c each? To save vertical space? I am thinking: Neat this is elegant and would work! But I can't think of any scenarios (off-the-cuff.) where I would choose this.

user_7832• 9 months ago

I have no idea how easy it is to implement this in KiCAD, but if it is - prototyping with this can be faster if you're eg making something like a DIY keyboard. Fewer things to solder, which is very nice if you struggle with it.

AnasMalas4• 9 months ago

It is as easy as 123, just a couple of clicks, and its all explained on the GitHub. However, unless you're committing to a 0.6 mm PCB, I wouldn't really use this on a keyboard, especially a full size one. The board really is not rigid at those sizes at that thickness. Weigh a tradeoffs and use it if it works for you!

AnasMalas4• 9 months ago

I made it for a business card, the whole card, PCB and components together, is 1.6 mm thick! That was my motivation for this

userbinator• 9 months ago

There are USB-A drives which do this, and in my experience they are far less durable than ones which have an actual connector. Given the thinness, this is going to be too easily snapped off.

kaoD• 9 months ago

I mostly use these for prototyping. Even gold-coated fingers still suffer from abrasion after many inserts so there is no way these are durable.

AnasMalas4• 9 months ago

Thanks for posting this! I have now updated the GitHub with test results for durability and to test PD capability. Have a look if you're considering using this!

PCB Edge USB C Connector Library

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