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Request for comments: USB C "trigger board" (feddit.it)
submitted 8 months ago* (last edited 8 months ago) by to c/electronics@discuss.tchncs.de
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Hello, first time poster (and also no significant EE background, so bear with me).

After receiving a batch of bad USB C PD trigger boards, I decided that it would be better if I made some myself. The design is taken from the CH224K datasheet. However, I am not sure if

  1. the schematic is correct
  2. the PCB is well laid out (I really struggled to fit everything)

Here is the schematic, and here is the PCB. Both are in a Codeberg repo.

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[–] [S] 1 point 8 months ago (2 children)

Wow, thanks! You’re not stepping on anyone’s toes. I’m a computer science guy that sometimes likes to dabble with electronics.

I haven’t looked at your PCB yet but I will considering merging this.

Also, how do I solder underneath the CH224K?

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  • [–] 2 points 8 months ago (1 child)

    Ooh it does have a thermal pad...

    In that case, I think you're on the solder paste train. Get it in a syringe, and use a small lure lock dispensing needle/tip to put a dab (about the size of the pad) on each pad. If dabs are touching a little bit, its okay, but if your board is absolutely covered in paste, you'll likely have problems.

    Then with a pair of tweezers (I like the ifixit 45° ones), you can carefully position each component so its legs touch down into the paste.

    Once all the components are on, you need to reflow it. A hot plate works, a clothing iron could work, you could even fill a junk/scrap pan (That will NEVER see food again) with sand and use the stove to heat the pan, removing it from the heat, and pulling the board with beefier tweezers once the paste has melted and wetted all the pads and pins.

    Since solder paste is just a bunch of tiny metal balls suspended in flux, so have a fume extraction plan. When it all melts, there will be some smoke/fumes from the flux that travel upward. Try not to breathe those in. A little bit won't kill you, but it is an occupational health hazard.

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