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how large to make surface mount pad?

Discussion in 'Electronic Design' started by Michael Noone, Jul 6, 2005.

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  1. Hi - I'm making a board with a slightly odd sized part. In it's datasheet
    there is no reccomendation for pad size - though they do give the size of
    the contact. (datasheet here:

    The part is a tantalum in a kemet B case size. The contacts are 2.2x0.8mm.
    How much bigger should I make the pads? Thanks!

    -M. Noone
  2. PeteS

    PeteS Guest

    Take this link

    Towards the end of the app note, you'll find the EIA recommended pad
    sizes for each case size

    If for some reason that doesn't come up, take the links in this order

    Browse by products
    TAJ series
    In the related information area, you'll see a link for 'technical
    summary and application guidelines'. That should take you to the PDF.


  3. legg

    legg Guest

    Check mfrs data, or google for 'IPC Calculator'. The latter references

    IPC-SM-782A - Surface Mount Design & Land Pattern Standard

    The standard is drawn from typical practice, it did not initially
    define it.

  4. qrk

    qrk Guest

    The "B" case size can be matched to a standard EIA case size. The data
    sheet shows the EIA case size as 3528. This has been a standard case
    size for SMT tantalums for the past 15+ years. Search for a 3528
    footprint on the web. IPC-SM-782A is a good starting place. I like
    using the recommendations that AVX gives over IPC.
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