Add AND9137_SO-3-8_EP_5x6mm_P1.27mm footprint

Ref https://github.com/KiCad/kicad-footprints/issues/1000

Datasheet: https://www.onsemi.com/pub/Collateral/AND9137-D.PDF

3d is already-existing ${KISYS3DMOD}/Package_SO.3dshapes/Vishay_PowerPAK_SO-8.wrl, which this footprint is specifically designed for.

This footprint almost exactly implements the footprint described in AND9137; the only difference is that this footprint has a .175mm radius on the top 4 pins because some guy on stackexchange suggested it's a good idea.

Another point of note is the pin numbering. Instead of numbering this as 1-8, I've numbered it 1-3. All packages that this claims compatibility for have source=1-3, gate=4, and drain=5-8. If you'd like to confirm compatibility yourself, here are the datasheets:

• http://www.farnell.com/datasheets/1704644.pdf
• http://www.vishay.com/docs/62839/si7149adp.pdf
• https://www.infineon.com/dgdl/irfhm9331pbf.pdf?fileId=5546d462533600a4015356237f7e1f59
• https://www.ti.com/lit/ds/symlink/csd18537nq5a.pdf
• http://aosmd.com/res/data_sheets/AON6236.pdf
• https://www.st.com/content/ccc/resource/technical/document/datasheet/d7/9b/35/84/f3/31/44/19/DM00098815.pdf/files/DM00098815.pdf/jcr:content/translations/en.DM00098815.pdf
• https://www.infineon.com/dgdl/DS_BSC014N04LS_2_1.PDF?folderId=db3a304313b8b5a60113cee8763b02d7&fileId=db3a3043353fdc16013552e99a8147f1
• https://assets.nexperia.com/documents/data-sheet/PSMN030-60YS.pdf
• https://www.renesas.com/us/en/doc/products/transistor/002/r07ds0765ej0200_rjk03m1dpa.pdf
• https://www.onsemi.com/pub/Collateral/FDMS86202-D.pdf
• https://toshiba.semicon-storage.com/info/docget.jsp?did=15504&prodName=TPW4R50ANH
• http://www.magnachip.com/powersolutions/down.php?filename=MDU3605.pdf
• https://www.rohm.com/datasheet/RS1E130GN/rs1e130gntb-e
• http://www.1mos.com/upload/file/UBIQ/QM4006M6.pdf
• https://datasheet.lcsc.com/szlcsc/1904151131_NIKO-Semicon-PKCH2BB_C384597.pdf
• https://datasheet.octopart.com/UPA2724UT1A-E1-AZ-NEC-datasheet-166712.pdf

Labeling the pins like this makes it possible to use the generic mosfet symbols in schematics.

The library conventions were carefully read and followed.

---

All contributions to the kicad library must follow the KiCad library convention

Thanks for creating a pull request to contribute to the KiCad libraries! To speed up integration of your PR, please check the following items:

• Provide a URL to a datasheet for the footprint(s) you are contributing
• An example screenshot image is very helpful
• If there are matching symbol or 3D model pull requests, provide link(s) as appropriate
• Check the output of the Travis automated check scripts - fix any errors as required
• Give a reason behind any intentional library convention rule violation.