Author Topic: Understading the footprint information from datasheet  (Read 617 times)

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Offline Sai tejaTopic starter

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Understading the footprint information from datasheet
« on: March 01, 2019, 01:56:04 pm »
Hello,

I am trying to draw a footprint of Type A Male USB connector for an application.

Details of the part are as follows:
Part Number :- 48037-0001
Datasheet :- https://www.molex.com/pdm_docs/sd/480370001_sd.pdf

In the datasheet sheet I am unable to find the radius of curvature for mounting pads at the ends. Please help me in this regard.

I am attaching the image of the footprint for the reference.

Thank you.
 

Offline T3sl4co1l

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Re: Understanding the footprint information from datasheet
« Reply #1 on: March 01, 2019, 02:13:14 pm »
Ends are semicircular, so radius equals half the pad width.

They don't dimension pads because those are up to the designer, PCB fab, and assembler to determine.

Typically an annular ring (pad radius minus hole radius) of 5 mil minimum is required, plus about half the hole radius.  So a 20 mil dia. hole gets 5 + (10 / 2) = 10 annulus, or 40 mil dia. pad.

Tim
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Offline Doctorandus_P

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Re: Understading the footprint information from datasheet
« Reply #2 on: March 01, 2019, 10:52:42 pm »
The only reason the holes have a radius is that the're supposed to be made with a mill.
perfect rectangular holes would also work, but are dificult (and therefore expensive) to make.

Beware of tolerances. you need a bit of room between the holes and the stuff that fits into the holes.

Size of pads are indeed not given. For machinal soldering you can get away with thin anular rings around the pads, but for hand soldering it's easier to make the pads a bit bigger, for better heat transfer from you soldering iron to the plated through hole.
 


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