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I have this component (LTST-FC12WEGBD-5A SMD LED by Lite-On) that has been very difficult to use due to the pad sizes being so small.

Below is the footprint.

The problem is with the smaller square pads (0.20mm x 0.20mm) with 0.1mm pitch. The component fails to make contact with the pads occasionally. I am hoping to fix this issue by extending the pads as show in the second image, represented by the red rectangles. The pitch will remain the same, but the length will increase. The hope is that additional solder paste will help in positioning, as well as contact. My fear is solder bridging.

Are there recommendations, or a reason I should not modify the footprint?

Recommended footprint:

Recommended Footprint

Modified footprint to increase pad length:

Modified Footprint to increase pad length

Part Drawing:

Part drawing

Images sourced or adapted from: DigiKey- Lite-On LTST-FC12WEGBD-5A datasheet

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  • \$\begingroup\$ What pcb finish/plating are you using? \$\endgroup\$ Jan 16 at 16:42

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My fear is solder bridging. Are there recommendations, or a reason I should not modify the footprint?

If there isn't enough solder, extending pads is a good way to add more solder. Its more of an art then a science however. It's unlikely that you'd get more solder bridging unless you were adding a lot of solder. That being said the pads look like they are being extended 4x the length, I would probably shoot for 2x, I've never had to extend pads more than 50-100% of the dimension I've extended them in.

There are also other ways to do this, like specify a thicker stencil. Make sure you are also using a good solder, and that it isn't expired if you are soldering these yourself.

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