SO vs SOIC packages - Do they differ between manufacturers?

[exe]

it takes you to the correct page on UltraLibrarian, where you can choose a variant if applicable, then download it. It offers a gazillion formats. Diptrace appears to be able to import Eagle footprints, so you'd download in Eagle format and then import it.

I just did that and it worked, thank you.

[exe]

Oh boy, I just used ultralibrarian for max6226, and it has wrong pinout. The pin 8 marked as GND, but it really is "Do not connect anything to this pin" (c) datasheet. You can check it here: https://app.ultralibrarian.com/details/4f419cec-7cff-11e9-ab3a-0a3560a4cccc/Maxim-Integrated-Products/MAX6226ALA25-T .

It's funny that they claim "Built to the Highest Standards" and "all of our available components have gone through a rigorous verification process". Worst part of  it is I don't see how I can report this. They have a contact form on the website, but they want my company name and phone number. Nonetheless, I submitted them a comment, but all I got back is "The website that you're trying to reach is having technical difficulties and is currently unavailable".

Moral of the story: do not trust component libraries.

[Siwastaja]

Moral of the story: do not trust component libraries.

This, this, this! Always, no exception. Whenever you think you finally found that really professional library service you really can trust, the next day you are reordering your PCBs because the footprints are wrong, again.

It's not a good idea to repeat the same mistakes all over again.

Just draw the footprints from the component datasheets. For additional security, cross-check against supposedly similar competitor part datasheet drawing and see what the differences are.

Once you get into this habit, it won't take long with any proper CAD tool.

[exe]

Just draw the footprints from the component datasheets.

Well, I did mistakes while drawing them . Sometimes drawings require a lot of calculation because they specify only "required" dimensions.

Verifying dimensions against the datasheet is easier because there is a ruler in my EDA. It takes me less time.

Anecdote story:  datasheet for a push button lacked drawings for exact part number that I bought. I had to measure the actual device.

[Siwastaja]

Just draw the footprints from the component datasheets.

Well, I did mistakes while drawing them . Sometimes drawings require a lot of calculation because they specify only "required" dimensions.

Exactly, and this is why library parts are risky: someone did draw them, making mistakes in the process!

The difference is: you are a professional / a hobbyist designer who's project's success depends on the suitability of the footprints. You are motivated to get them right, possibly even well paid for your time. You re-check for just that particular part. Often you even have the physical part to check against. So it's to be expected you are better on average than some anonymous intern somewhere who was just tasked to draw 1000 footprints. Or worse, someone just combined some re-re-re-labeled footprints that have been lurking around for decades under different names, from different EDA tools. If your success rate in creating a correct footprint is like 99%, some library may have just 90%, which is a disaster.

In either case, it's best to recheck the footprints at a different design stage than when the footprints were first drawn. For example, measure from the Gerber output, comparing to a physical part you ordered for prototypes. Fresh set of eyes help.

[phil from seattle]

Moral of the story: do not trust component libraries.

This, this, this! Always, no exception. Whenever you think you finally found that really professional library service you really can trust, the next day you are reordering your PCBs because the footprints are wrong, again.

It's not a good idea to repeat the same mistakes all over again.

Just draw the footprints from the component datasheets. For additional security, cross-check against supposedly similar competitor part datasheet drawing and see what the differences are.

Once you get into this habit, it won't take long with any proper CAD tool.

Ditto. Essential skill for a PCB designer. Just do it.

Back in the old days of Eagle there were so many bad footprints out there that I got in the habit of making my own.  Footprint editor on one screen, datasheet on another. Pretty easy and fast once you do it a couple of times.

Drawing a good footprint from a datasheet is not very hard at all. You just need to get creative with grid size and be smart about picking your origin.  For complex ones, have a spreadsheet open on another screen. Eagle has a user definable alternate grid available - hold alt down and get it. Works pretty well. In Kicad, I use property sheets to set exact size, location. Even big, complex parts are pretty fast.

The point about checking competitive offerings is a good one.  I will tweak a given footprint to make sure it will support alternate chips so I can use them without PCB redesign.

[gnuarm]

My issue/question is whether it is correct that a Nexperia SO14 differs from a TI SO14,

Well, if we are talking about CD40106, then in datasheets for CD40106 from Nexperia and TI have same dimensions and pitch.

Have you checked the exact suffix on the parts you have against their datasheets?

Not sure I understand you, I only checked "box" dimensions for what I'd call soic-14. Fortunately, they have non-overlapping suffixes, so it's impossible to get a part in unexpected package. Both have ordering information on the very first page, which super helpful to me.

Btw, LCSC provides photos of actual parts, so it's easy to do some at least some sanity check: https://lcsc.com/product-detail/4000-Series_HGSEMI-CD40106BMTR_C194331.html .

Until they don't. Never ever rely on pictures in catalogs or datasheets. Always use the dimensional drawing which matches the package / order code and check that against the footprint in your PCB design program. It helps to have a part database which stores the manufacturer's order code together with the symbol and the footprint. That way you have to do this thourough check only once.

The LCSC photos are often wrong as are their descriptions (although they are mostly just incomplete).  I've always wondered who provides the inputs for the disti's data bases.  I suspect it is from the manufacturer rather than the disti.  In the case of LCSC I suspect it is LCSC and they seem to put little effort into it.  Digikey and Mouser are much, much better.  The both also have a link on every web page for you to report errors which I frequently use.  They both are very responsive in fixing problems even fixing common problems across a product line rather than the single item you might report.  Digikey rocks! 

[gnuarm]

Yes, a distributor picture can warn you about a possible mismatch but that's the last line of defence, don't trust it alone, always check properly.

Also be very careful to verify that,
1) distributor datasheet pdf link really opened the right file
2) datasheets relevant to multiple different part numbers, read the correct sections.

Drawing / verifying correct footprints is somewhat time-consuming and feels like a daunting task first but once you make it your default process, you'll see it isn't too bad, even a single fuck-up costs more time than verifying 1000 footprints.

All great advice.  The sort of thing normally learned the hard way. 

One of the things that is hard to get hobbyists to accept is that they should just bite the bullet and enter their own footprints and thoroughly check them.  As you say, do you want to deal with your own mistakes or deal with other's mistakes?  The time spent vetting someone else's footprint is nearly as bad as just doing it yourself.

I wish there was more reliable info on how to turn package dimensions into a footprint.  There are recommendations, but they even vary depending on mode of assembly and your "process".  So in other words, no real standard.  I was surprised to learn manufacturer recommendations are different between capacitor and resistors of the same size! 

[gnuarm]

Just draw the footprints from the component datasheets.

Well, I did mistakes while drawing them . Sometimes drawings require a lot of calculation because they specify only "required" dimensions.

Verifying dimensions against the datasheet is easier because there is a ruler in my EDA. It takes me less time.

Anecdote story:  datasheet for a push button lacked drawings for exact part number that I bought. I had to measure the actual device.

Yeah, companies who can't be bothered to publish a proper data sheet don't get my business.  I'm just not going to risk a design success for a part that may or may not match a datasheet if they can't be bothered to provide the datasheet data that the part may or may not match on any given day.