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Using Canned Free Libraries from Various Vendors

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Tom H View Drop Down
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    Posted: 06 Jun 2022 at 12:34pm

With the free canned PCB libraries out there, you get a solder pattern that only has features that were manually created by someone, and you must add all the features you want in your CAD tool.

Did it come with:

  • Silkscreen Outline under the package that is not visible after assembly?
    • Silkscreen Outline line width that you use that are consistent with your master library?
  • Visible polarity marking for post assembly inspection?
    • Is the Polarity Marker the right size, shape and location you want?
  • Component and Terminal Outlines so you can see exactly where they are in relation to the pad pattern?
    • Terminal Outlines provide visual assistance for the solder joint goals for Toe, Heel and Side.
  • Contoured Courtyard Outline that represents your internal design rules for part placement guidelines?
    • Courtyard Excess for various packages may differ and range from 0.10 mm to 1.00 mm.
  • Was the footprint delivered with the units you use?
    • Metric, mils, inches, micrometers?
  • What design rules were used for the pad size and space calculations?
    • Are they consistent with all the footprints from the same vendor?
  • Is the pad shape consistent with your company guidelines?
    • Rectangle, Oblong, D-Shaped, Rounded Rectangle?
  • Do they always have the footprint you are looking for?
    • If not, will they create it for free in the time frame you need it?
  • Is the footprint origin on Pin 1 or in the center or offset?
  • Are the pads for low profile packages trimmed from under the package?
  • Are the pad stack sizes rounded 2 (0.01) or 3 places (0.001) to match your master library?
  • Does the footprint come in 3 Tiers for Least, Nominal and Maximum density levels?
  • Does the footprint come with the correct solder mask oversize?
  • If the footprint has a thermal tab, is the paste mask reduction 60%?
    • Does the Paste Mask apertures have at least 0.20 space between them?
  • Does the footprint come with a 3D model imported into it?
  • Is the Zero Component Orientation (Pin 1 location) consistent with your master library?
  • Is the Footprint IPC-7351B compliant or did they just make up the footprint name?
    • Or did the supplier use the PCB Libraries, Inc. proprietary Footprint Naming Convention in violation of the PCB Libraries, Inc. copyright?
  • If the user changes CAD tools, can they rebuild the new library in minutes?

These are just a fraction of all the things a user must consider when using Stock Libraries. 

V2022 Footprint Expert allows the user to set Options for all of these PCB library features for the creation of 100% consistent library quality.

V2022 Footprint Expert allows the user to save the package dimensions and apply different rules for the batch creation of various libraries for multiple applications.

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