Easy Type-C, Finally
It has been a while since USB Type-C became popular but I still avoided it for my hobby designs. It wasn’t due to its performance, oh no - performance was much better than what I needed. You see, I still use USB 2.0 for literally all my electronics projects. While not fast in the grand scheme of USB, it’s plenty fast for serial communication and that’s what I end up designing my gadgets around 90% of the time. My issues with the connector were due to soldering. Hand-soldering, to be precise.
Most of the type-C receptacle designs are of surface-mount kind. On its own that’s not an issue - I’ve hand-soldered my share of finicky narrow pitch ICs. Issue is the location of 24 pins that are needed. While 12 pins are almost reachable by a thin soldering iron, the other 12 pins are usually under the device. Not an issue if you are making them professionally or even in an oven but impossibility for soldering by hand.
And no, you cannot solder just one side of connector and be compliant. It doesn’t matter if you’re only interested in USB 2.0 as I was - you still need to connect both sides as you need to connect 5.1K resistor for device to be properly recognized. And yes, even if you fail to do that it will work with the type-A to type-C cable. It will sometimes work even with the type-C to type-C. However, things that happen only sometimes have a nasty habit of happening at the most unfortunate time.
Connectors that used a combination of through-hole design and surface-mount pads looked promising on the paper. The unreachable pads underneath were converted to pins and soldering problem got solved. Unfortunately, a lot of such connectors had a shield over the rear pads. Now rear pads became a problem. I did find a few with more open space that were easier to hand-solder but at a pricey $3.
But finally, I found the type-C connector that suits my use case perfectly - USB4085-GF-A. It’s an USB 2.0 connector that allows connection to 16 out of 24 type-C pins. The sacrificed pins mean that you won’t ever be able to use it with the high-speed devices (thus 2.0 moniker). However, the pins that remain include not only all the standard USB 2.0 power and data connections but also CC1 and CC2. These two pins are really important if you want your device to be part of the type-C universe and pull 1.5 A of current. The only thing needed in addition to the old type-A designs is two 5.1K pull-down resistors on each of those pins and you’re golden.
Mind you, the connector is not perfect. At $1.50 it’s a bit pricey but not excessively so. If you are using the standard 1.6 mm PCB, you will need to take a great care to position it flush in order for short pins to even reach to the other side. Hole spacing means you will need to use 6/6 PCB manufacturing which, while often supported, is still a bit less common than bog-standard 8/8. But these are all minor issues and hand-soldering is a breeze.
And despite all this goodness, I only used it for a few test contraptions and not in any of my proper projects. This is due to its biggest drawback - there is only one manufacturer and, outside of my initial purchase, they are pretty much on backorder the whole time. Even at the time of this writing, the quantity is 0 on DigiKey.
Once this connector becomes more available, I am looking forward to using it.
PS: For those wanting to have type-C plug directly on the board, there is a Molex 105444-0001. Just don’t forget to order 0.80 mm PCB.
PPS: For the 90° type-C connector, KUSBX-SL-CS1N14-B looks promising as it also allows connection to both CC1 and CC2 - a necessity for the proper type-C device. I haven’t tried it myself though.