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Electronics => PCB/EDA/CAD => KiCad => Topic started by: scientist on January 30, 2014, 10:51:03 pm

Title: SOIC-24-WIDE not actually wide
Post by: scientist on January 30, 2014, 10:51:03 pm
I have a board I'm building based on the TLC5926 shift register, and the obnoxious bit about KiCAD is that the footprint labels are lying. They say SOIC-24, as the TLC5926s do, but when I get boards manufactured, the chips are too wide and the pins extend several millimeters past the pads. As a solution, I have in the past edited each module in the board with ModEdit to lengthen the pads to 2 mm long, but now when I try to replace the footprint in the board with it, two of the pins just fly off to the side, never to return. It's absolutely maddening.


Actually, the KiCAD SOIC-24-W file is what I was using (incorrectly). The actual SOIC-24-WIDE file fits fine but doesn't have any extra pad to make soldering easier.
Title: Re: SOIC-24-WIDE not actually wide
Post by: mikeselectricstuff on January 30, 2014, 11:47:39 pm
This is not  a Kicad problem, it's an "I forgot to check" problem.
Title: Re: SOIC-24-WIDE not actually wide
Post by: c4757p on January 30, 2014, 11:50:13 pm
The flying pins is a bug that's been around for some time. Occasionally it does that when you save the footprint. Restart Kicad, open it, move them back and resave.
Title: Re: SOIC-24-WIDE not actually wide
Post by: scientist on January 31, 2014, 12:14:34 am
This is not  a Kicad problem, it's an "I forgot to check" problem.

I didn't "have them manufactured" per se... I made them myself, then slapped myself for doing it wrong. Total loss about $2 of FR4, no big deal.
Title: Re: SOIC-24-WIDE not actually wide
Post by: scientist on January 31, 2014, 06:00:55 pm
Actually, I stand corrected... the SOIC-24-WIDE file is the correct size, while the SOIC-24-W is just the normal soic24 with slightly wider plastic packaging.
Title: Re: SOIC-24-WIDE not actually wide
Post by: madworm on January 31, 2014, 06:15:52 pm
Check the datasheet of the part and try to find a footprint somewhere in some library. If successful, verify it is correct and add it to your own library. If you can't find a footprint, make one yourself.

There is simply no other way.