When designing PCB's, I find myself very often having to make footprints for a significant portion of the components on my board. This tends to be very time-consuming, as (in Altium at least), dimensioning out land patterns for strange connectors or chips (those that can't be created from a wizard) isn't very easy. It seems like anyone that uses these chips or connectors would need a footprint, so I can't understand why these aren't more commonly provided. For example, right now I'm trying to put a USB 3.0 Micro-B connector on a board, but the top 5 connectors on Digikey don't seem to provide footprints. I have access to the Altium Live design content, but even that seems often pretty out-of-date.

I feel like there's something obvious that I'm missing - or else this system seems very inefficient (which usually isn't the case). Can someone enlighten me?

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    Because it is so easy to draw them yourself from the values in the datasheets? – PlasmaHH Jun 30 '15 at 13:51
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    Maybe my skills are lacking, but without Solidworks-style dimensioning tools (or anything better than just a grid), drawing out a footprint for a part like this would take me at least 15 minutes -which seems not-trivially time expensive and pointless for everyone who uses the part to have to do over and over. – zplizzi Jun 30 '15 at 13:56
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    Experienced PCB designers create their own footprints. Supplied libraries often have errors. – Leon Heller Jun 30 '15 at 13:57
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    @Umar TI, for example, provides footprints in the Ultra Librarian format, which has a free version that allows conversions to most design packages. And I guess I do need more practice, but it still seems like you're more liable to make a mistake doing it quickly than using something the manufacturer designed and double and triple-checked. – zplizzi Jun 30 '15 at 14:02
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    I dearly wish PCB CAD tools incorporated proper dimensioning tools in their footprint editors. – Nick Johnson Jun 30 '15 at 14:06
up vote 17 down vote accepted

You've discovered the dirty little secret of the EDA industry: Thousands of engineers everywhere reinvent the wheel every day - they all create many of their sch symbols & pcb footprints from scratch. It is quite ridiculous.

However there are reasons for it, in particular no universal (or even common) file format (nor for the schematics & PCB designs either), and that's in large part the fault of the various EDA software developers, who rely on this lack of file format compatibility to keep customers locked in.

Until recently there's also never been a way to have confidence in 'random' other people's sch/PCB-footprint designs, so E.E.s err on the side of caution and make most of them themselves. But now there are some options, like snapeda.com and circuithub.com.

When I was working as an engineer, I wondered the same thing, which is why I decided to create SnapEDA.

SnapEDA is a CAD library of 25 million electronic components, for which we provide PCB footprints and schematic symbols. Our PCB footprints convert to Altium, OrCad/Allegro, Eagle, KiCAD, & Pulsonix.

We run a diagnostic test on each CAD file, which we'll be making public in the next month or so. This checks for different aspects that might go wrong with mappings, silkscreen overlaps, etc.

In the future we plan to expand to other forms of design data as well.

Would love to know what you think if you have some time to check it out. We love getting feedback, and everyday we are continuing to refine the product to make it even better!

  • This looks awesome! Just out of curiosity, on the front page I see a number that says 27177 footprints, while I also see (and you claim) 25 million components. Are there just a lot of components without footprints yet? – zplizzi Jun 30 '15 at 18:20
  • Thanks! Good question. Our library is 25 million electronic components (datasheets, specs, pricing etc). And our footprints have a 1-N mapping across the components. We're still working on what our exact coverage is, but it's in the millions for CAD data, and will be growing significantly this month as we work on improving our mappings. So yes, there are some without CAD data now, but when they don't have CAD data, you can easily request it from the community too (see the "Requests" page: snapeda.com/part-requests – natab Jun 30 '15 at 18:35
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    Ohh! Of course, silly me. That's awesome, I'll definitely use this in the future. – zplizzi Jun 30 '15 at 18:48
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    Great!! What we've learned is that engineers/designers have really personal preferences when it comes to their CAD data, so we're working on more ways to incorporate that. Even something as simple as how pins are arranged on a symbol, for example. For footprints, we are following IPC standards mainly. Keep us in the loop of how things go! – natab Jun 30 '15 at 19:07
  • Searching for "GPS" returns a bunch of things with pricing information and no footprints. This one doesn't even seem relevant and this one seems to be plain wrong. – David Jul 1 '15 at 11:56

In the mechanical world a 4-40 screw, is a 4-40 screw. In electronics, we don't have that luxury. Every PCB is different. The footprint for even an 0805 resistor will be different for wave vs. IR reflow vs. hand soldering. Some boards are small and dense, other larger and sparse. It's just easier to assess the design requirements, and tailor footprints to fit them. Never mind the issue of having to go through and verify that Joe Blow's footprint he put in some library is correct, and then making it fit the design requirements.

If you are willing to spend money, you can acquire the IPC footprint wizard tool:

http://landpatterns.ipc.org/default.asp

That tool is really easy to use. Literally, you just copy/paste the measure of the mechanical data furnish by your supplier and the IPC wizard take care of drawing you a sweet footprint. I made a 62 pins MCU footprint in less than 3 min with that tool. Here a little demo from youtube: https://www.youtube.com/watch?v=8V0ZfLsp8gY

If you don't want to pay for the IPC wizard, AD include a component wizard in the footprint creator, however it is more hard to use it and often you end up with a footprint that need manual rework. So you can understand that the main reason why footprint aren't online is because most people are using footprint generator therefore, it take less time to literally make a footprint than search for it on the internet.

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