Mounting a USB Connector - Page 1
Forum section: electronics / projects

author: MCPorche
author_rank: Contributor
timestamp: August 28, 2014, 09:45:10 pm
content: Ok, I feel really stupid...I have a dual USB connector that I am trying to mount on a PCB. There are 8 through-hole pins, and I have my footprint set up for that.However, there are four angled tabs on the connector that won't allow the connector to sit low enough that I can solder the pins. Am I supposed to drill holes in my PCB for these tabs? Or, what?Thanks.

author: Whales
author_rank: Super Contributor
timestamp: August 28, 2014, 09:49:39 pm
content: Yes. These clip onto your board through holes.

author: rs20
author_rank: Super Contributor
timestamp: August 28, 2014, 10:20:08 pm
content: Quote from: MCPorche on August 28, 2014, 09:45:10 pmThe datasheet for the connector will include a suggested PCB hole drilling layout which will include holes for these tabs, placed in just the right place so they click in nicely. The hole should part of your footprint, and should be through-plated like everything else, and typically you'll solder these tabs down just like any other electrical pin (but for mechanical support purposes).

author: MCPorche
author_rank: Contributor
timestamp: August 30, 2014, 04:45:50 pm
content: Sadly, the datasheet is SEVERELY lacking. I ended up ordering another type from a different vendor.The datasheet shows the spacing laterally between the set of pins for one of the USB connectors, but doesn't show the spacing between the two rows of connectors. It also doesn't show the spacing/size for the holes for the tabs.

author: miguelvp
author_rank: Super Contributor
timestamp: August 30, 2014, 06:47:12 pm
content: Quote from: MCPorche on August 30, 2014, 04:45:50 pmThat is very odd, do you have a link?For example this datasheet seems very clear on the pcb mount spacing.

author: MCPorche
author_rank: Contributor
timestamp: August 30, 2014, 07:58:07 pm
content: Yeah...here's the link to the only datasheet I can find on this particular connector.http://www.jameco.com/Jameco/Products/ProdDS/2076551.pdf

author: Matje
author_rank: Regular Contributor
timestamp: August 30, 2014, 10:29:07 pm
content: Quote from: MCPorche on August 30, 2014, 07:58:07 pmBad / incomplete / butchered datasheets unfortunately are a fact of life.At least for reasonably standardized parts (many connectors, all sorts of chip packages etc.), if you are missing dimensional or footprint data it helps to search for other manufacturers datasheets and look at what's in there.Sometimes all that is needed is to get the actual manufacturers datasheet instead of the distributors butchered version.

author: Falcon69
author_rank: Super Contributor
timestamp: August 31, 2014, 06:29:32 am
content: When I could not find a data sheet footprint, I simply made up the hole patterns and printed it off in full scale using photo paper (gave the best resolution) and then placed the component on the paper and adjusted the holes till it was correct. Ordered the boards, and all was good. You may have to play with your printer to find out the correct scale so it comes out in TRUE scale format. That's easy to do, simply get a part that you KNOW the footprint for, like a header pin with 1.27mm or 2.54mm spacing, and check printer settings with that, then play around with the footprint for your part.It's a process, a slow one, but it does work.

author: miguelvp
author_rank: Super Contributor
timestamp: August 31, 2014, 06:39:10 am
content: I'll be surprised if the image I linked didn't match the OP partUnless I'm missing something it seems the dimensions on his datasheet match those in the picture.

author: MCPorche
author_rank: Contributor
timestamp: September 02, 2014, 02:47:01 am
content: Can you provide a link to that image?It's too small to make out any detail. Thanks.

author: miguelvp
author_rank: Super Contributor
timestamp: September 02, 2014, 02:50:33 am
content: is the same one I posted before, for whatever reason it selected the small thumbnail instead, but I was drinking :p

author: Hardcorefs
author_rank: Regular Contributor
timestamp: September 02, 2014, 11:30:00 pm
content: Quote from: MCPorche on August 30, 2014, 04:45:50 pmI recently had to do a 50 pin device, the measurements are taken from a split line and assumed to be central to that line NOT drill central.So basically you have to measure the distance to the split line then indulge in addition/subtraction/division, rather than it being from the center of each pin!!The outer pins are 13.14 drill central apart, which means they are 6.57 from the mid linepins 2& 3 are 2 drill central apart which means they are 1 from the split line, so there you have it (6.57-1) the outer pins are 5.57 from pin 2 /pin 3 drill centreHave a look at the attachment 0.5X23=11.5, to see just how complex it can get….

author: G7PSK
author_rank: Super Contributor
timestamp: September 03, 2014, 07:47:02 am
content: Quote from: MCPorche on August 30, 2014, 07:58:07 pmThe mounting pin positions are found by from the measurements provided on the drawing, 12.mm wide 3.72 from the front and 10.28 from the back the whole thing is 16.96 long so they are 2.96 apart.

author: MCPorche
author_rank: Contributor
timestamp: September 03, 2014, 12:35:58 pm
content: Isn't that 3.72 how long the tabs stick out from the bottom if the connector body?Sent from my iPhone using Tapatalk

author: jmole
author_rank: Regular Contributor
timestamp: September 03, 2014, 12:48:00 pm
content: Quote from: Hardcorefs on September 02, 2014, 11:30:00 pmshit like this makes me wonder why semiconductor mfg's don't just have DXF/DWG files for footprints. Would make life a hell of a lot easier.This one was *lots* of fun...

author: tautech
author_rank: Super Contributor
timestamp: September 03, 2014, 01:15:09 pm
content: Quote from: MCPorche on September 03, 2014, 12:35:58 pmYes, slightly more than the pins themselves.And commonly soldered to GND tracks also.

author: MCPorche
author_rank: Contributor
timestamp: September 03, 2014, 01:17:02 pm
content: Sorry, I forgot to quote the post. The post I was replying to said that the 3.72 was the distance from the back of the connectirSent from my iPhone using Tapatalk

author: DanielS
author_rank: Frequent Contributor
timestamp: September 03, 2014, 01:24:21 pm
content: Quote from: Hardcorefs on September 02, 2014, 11:30:00 pmThat is a fairly simple drawing but inconsistent referencing does make interpretation more difficult than it should be.Good thing you can simply attach measurements to your footprint design to crosscheck things as you go.

author: Whales
author_rank: Super Contributor
timestamp: September 04, 2014, 10:04:44 am
content: Quote from: jmole on September 03, 2014, 12:48:00 pmI'm going to print that out and place it at select locations in my uni. Passive sadism.

author: tszaboo
author_rank: Super Contributor
timestamp: September 04, 2014, 12:11:50 pm
content: Quote from: DanielS on September 03, 2014, 01:24:21 pmI hate connector datasheets. They are done by mechanical engineers who never designed anything PCB related in their life. Its like building a house which was designed by someone who never seen one. Really annyoes the hell out of me. First thing is that they just have no idea what a reference point is. And putting the most useless information on the datasheet, check. I really dont care, where the internal latching thingie is, it is standardized, but please tell me the what I have to put on the PCB. And dont crowd your drawing with material data agency approvals, signatures, and have one drawing for a series with RA connections raging from 4 to 54 pins. And how about putting a picture of your thing anywhere.

author: sacherjj
author_rank: Frequent Contributor
timestamp: September 04, 2014, 12:35:48 pm
content: Yep, when you have to get out Excel to figure out the actual coordinates of an offset of an offset, something is totally wrong.

author: tautech
author_rank: Super Contributor
timestamp: September 04, 2014, 07:57:30 pm
content: Quote from: NANDBlog on September 04, 2014, 12:11:50 pmI quite agree and they can easily place a link to the footprint model for download but alas they rarely do.For me, the overall measurement is the primary concern to ensure it will fit in the desired location, then try and find the/a footprint download or just make one.