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Everything Else » PCB Design for Female Header with Weld Tabs

June 29, 2014
by jlaskowski
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I purchased a female header for a PCB. In addition to it's 20 connection pins, it has a weld tab on each end. The weld tabs are .025" wide by .01" thick.

I am using Cadsoft Eagle to design my 2-layer PCB.

Questions:

1) What should I add in my PCB design for these weld tabs? Just holes? Should I add a pad instead of just a hole so there's some copper to solder them to? If yes, do all pads automatically have copper on the bottom side (even if they aren't connected to anything else on the board)?

2) The tabs are rectangular, not circular. Is my only option a round hole?

3) If I go with a round hole, since the tabs are .025" X .01", should I make my hole .031? Choices in range are .027, .031, and .035.

July 01, 2014
by sask55
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Jlaskowski

I have had good success finding component layouts on element 14. perhaps you could have a look thru the Samtec libraries and locate a connector layout that is already designed for the connectors you are using. I have found that most components and devices will have a layout available in a preexisting CAD library all that is required is to download the library select the desired device, place the device in the schematic and locate it on your board layout. Samtec library link

July 01, 2014
by scootergarrett
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From what I can tell it looks like you should put holes (vias) for the 'weld tabs' to go through then you would solder then in from the other side. As far as eagle I think you don't have to connect each pad to something on the schematic. I'm in the eagle boat lately but I have had good luck with downloading schematic from Newark.

July 02, 2014
by BobaMosfet
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jlaskowski-

Yes, just create a via-- I would make it in the ground-plane, doesn't have to be connected to anything else, unless you want to connect it to ground.

Footprint PDF

BM

July 03, 2014
by jlaskowski
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Thanks for the replies, Gents. I looked for this component and several others I have on Element14 and they aren't there. I haven't had much success either finding libraries for the company whose part I have or, when I do, finding the parts themselves. So, I made my own library and have been designing the components there myself.

BobaMosfet, thanks for the link to the suggested layout for this component. Having never made a board before, I was wondering for all my components how much bigger of a hole I should make than the size of the pin. For this component, the layout you pointed me to makes it clear. If anyone has a general rule of thumb as far as pin diameter to hole diameter ratio, please let me know what it is. I'd hate to send this board off for manufacturing and not be able to get my components attached due to small holes (or have a difficult time soldering because they're too big).

I can't add vias to a custom component in Eagle. There only seems to be an option to add them on the board design as separate from components. I would rather add it to the component so they move with the header. Otherwise I have to precisely reposition them each time I move the header. With that in mind, I can add pads to the component. Is there anything wrong with adding it as a pad instead of a via?

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