EEVblog Electronics Community Forum
Electronics => Projects, Designs, and Technical Stuff => Topic started by: MCPorche on August 28, 2014, 09:45:10 pm
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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.
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Yes. These clip onto your board through holes.
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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.
The 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).
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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.
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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.
That is very odd, do you have a link?
For example this datasheet seems very clear on the pcb mount spacing.
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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 (http://www.jameco.com/Jameco/Products/ProdDS/2076551.pdf)
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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 (http://www.jameco.com/Jameco/Products/ProdDS/2076551.pdf)
Bad / 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.
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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.
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I'll be surprised if the image I linked didn't match the OP part
(https://www.eevblog.com/forum/index.php?action=dlattach;topic=35733.0;attach=107197;image)
Unless I'm missing something it seems the dimensions on his datasheet match those in the picture.
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Can you provide a link to that image?
It's too small to make out any detail. Thanks.
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is the same one I posted before, for whatever reason it selected the small thumbnail instead, but I was drinking :p
(https://www.eevblog.com/forum/projects/mounting-a-usb-connector/?action=dlattach;attach=107196;image)
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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.
I 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 line
pins 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 centre
Have a look at the attachment 0.5X23=11.5, to see just how complex it can get….
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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 (http://www.jameco.com/Jameco/Products/ProdDS/2076551.pdf)
The 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.
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Isn't that 3.72 how long the tabs stick out from the bottom if the connector body?
Sent from my iPhone using Tapatalk
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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.
I 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 line
pins 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 centre
Have a look at the attachment 0.5X23=11.5, to see just how complex it can get….
shit 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...
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Isn't that 3.72 how long the tabs stick out from the bottom if the connector body?
Yes, slightly more than the pins themselves.
And commonly soldered to GND tracks also.
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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 connectir
Sent from my iPhone using Tapatalk
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Have a look at the attachment 0.5X23=11.5, to see just how complex it can get….
That 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.
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This one was *lots* of fun...
I'm going to print that out and place it at select locations in my uni. Passive sadism.
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Have a look at the attachment 0.5X23=11.5, to see just how complex it can get….
That 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.
I 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. [/rant]
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Yep, when you have to get out Excel to figure out the actual coordinates of an offset of an offset, something is totally wrong. :--
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Have a look at the attachment 0.5X23=11.5, to see just how complex it can get….
That 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.
I 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. [/rant]
I 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.