IDC connectors aren't supposed to be difficult.... - Page 1
Forum section: electronics / projects

author: jrmymllr
author_rank: Regular Contributor
timestamp: September 24, 2025, 09:17:10 pm
content: I'm trying to find mating connectors for a single board computer. The supplier is of little help despite how much these things cost. No, it wasn't my decision.There's two shrouded dual row IDC connectors with a 2mm pitch, but the problem is there's very little space beyond the last pin. So something likehttps://www.digikey.com/en/products/detail/cnc-tech/3130-20-0102-00/3883444doesn't work because it's too long because of the latch at the ends.This one also doesn't work because it's still too long by about 0.8mm:https://www.digikey.com/en/products/detail/amphenol-cs-fci/89947-720LF/1090141I think this one will work but I don't have it in my hands yet to try, but ouch expensive and the only one I can find:https://www.digikey.com/en/products/detail/te-connectivity-amp-connectors/1-111626-9/765791Anyone come across this?

author: thm_w
author_rank: Super Contributor
timestamp: September 24, 2025, 09:50:27 pm
content: Photo would help.Maybe they expect you to use a crimped connector.

author: jrmymllr
author_rank: Regular Contributor
timestamp: September 24, 2025, 10:07:08 pm
content: Quote from: thm_w on September 24, 2025, 09:50:27 pmIt's just one of these, but about as small of a footprint as possible.EDIT: Did just find these on another design. Never came up in Digikey for whatever reason. Not sure yet if we'll use crimped or ribbon.https://www.digikey.com/en/products/detail/molex/0511102051/267674

author: Smokey
author_rank: Super Contributor
timestamp: September 24, 2025, 10:18:30 pm
content: Use the crimp pin versions?https://www.digikey.com/en/products/detail/amphenol-cs-fci/90311-028LF/1090048I'm not saying this is a great idea, but in a pinch I've superglued the strain relief on an IDC cable and then cut off those "latches" on the sides.

author: Someone
author_rank: Super Contributor
timestamp: September 24, 2025, 10:24:50 pm
content: Quote from: thm_w on September 24, 2025, 09:50:27 pmOr even just the name/part/manufacturer of the board in question!Quote from: thm_w on September 24, 2025, 09:50:27 pmLots of modules expect you will use a board to board connector, even if there are mating wire to board options in the line.

author: thm_w
author_rank: Super Contributor
timestamp: September 24, 2025, 10:36:27 pm
content: Quote from: jrmymllr on September 24, 2025, 10:07:08 pmLooks like a standard USB3 motherboard header, but 2mm pitch instead of 2.54mm. Are they using it for some other signals?edit:https://www.asus.com/ca-en/support/faq/1052532/https://www.aliexpress.com/item/1005008962582413.html

author: wraper
author_rank: Unknown
timestamp: September 24, 2025, 10:45:49 pm
content: This is clearly USB 3.0 motherboard to front panel connector. Nor it's a standard IDC connector, nor you should use a ribbon cable with it (must be shielded twisted pairs for data lines)https://www.toby.co.uk/uploads/publications/1869.pdf

author: thm_w
author_rank: Super Contributor
timestamp: September 24, 2025, 10:49:12 pm
content: Quote from: wraper on September 24, 2025, 10:45:49 pmYou need to find the 2.00mm version of that though, or a 2 -> 2.54 adapter.

author: wraper
author_rank: Unknown
timestamp: September 24, 2025, 10:50:57 pm
content: Quote from: thm_w on September 24, 2025, 10:49:12 pmUSB 3.0 never used 2.54mm pitch.

author: thm_w
author_rank: Super Contributor
timestamp: September 24, 2025, 10:56:50 pm
content: Quote from: wraper on September 24, 2025, 10:50:57 pmah now it all makes sense, well super easy to find at any computer store then.

author: jrmymllr
author_rank: Regular Contributor
timestamp: September 24, 2025, 10:58:11 pm
content: Quote from: Smokey on September 24, 2025, 10:18:30 pmThis needs to be good enough for production which the crimp pins would be, unless it moves in the direction of requiring ribbon.

author: wraper
author_rank: Unknown
timestamp: September 24, 2025, 11:03:12 pm
content: If you need this for mass production, just go to whichever company makes these computer cables.https://www.mcccable.com/sale-40992423-usb-3-0-front-panel-motherboard-19-20-pin-cable-to-usb-female-splitter-adapter-extension-connector.htmlTrying to make these yourself is absolutely stupid. It's akin of making your own USB cable to charge your phone.

author: jrmymllr
author_rank: Regular Contributor
timestamp: September 24, 2025, 11:03:30 pm
content: Quote from: Someone on September 24, 2025, 10:24:50 pmThe part number of the board really won't help, trust me! They do not give any further information than what I have (which is nothing really). The supplier gave me part numbers of the board connectors but they are some weird Asian brand that is almost, not completely, but almost completely devoid of useful information and not on LCSC, DK or Mouser.

author: jrmymllr
author_rank: Regular Contributor
timestamp: September 24, 2025, 11:04:59 pm
content: Quote from: thm_w on September 24, 2025, 10:36:27 pmThat one is USB yes. But there's another, lower pin count version also on the board for audio that I have the same issue with.

author: jrmymllr
author_rank: Regular Contributor
timestamp: September 24, 2025, 11:06:00 pm
content: Quote from: wraper on September 24, 2025, 10:45:49 pmTrue, but I have the same issue with a lower pin-count audio connector of the same style.

author: jrmymllr
author_rank: Regular Contributor
timestamp: September 24, 2025, 11:07:10 pm
content: Quote from: wraper on September 24, 2025, 11:03:12 pmCorrect, but I also need a 10 pin version for audio.

author: wraper
author_rank: Unknown
timestamp: September 24, 2025, 11:14:06 pm
content: QuoteAzalia connector uses 2.54mm pitch and it's a pin header with no shroud. You can plug whatever onto those. But normally it's a dupont connector that's plugged onto those as you cannot crimp shielded cable to IDC plug.

author: jrmymllr
author_rank: Regular Contributor
timestamp: September 25, 2025, 12:54:45 am
content: I believe I have this figured out now so thank you to everyone. I was so focused on finding mating connectors for everything I didn't think about how we're not going to build a USB cable. But, I also have another connector that is the same way that we will have to make a cable for (probably will, it's still early), but the mating ribbon connector for that one is simply going to be expensive I believe. The individual wire crimp type is really cheap however cost may not be too important.