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Is there an official SMT size site?

Discussion in 'Electronic Design' started by Joerg, Jan 24, 2007.

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  1. Joerg

    Joerg Guest

    It's bewildering. Was looking for diodes in SC-75, barely anything. Then
    by chance I found the beloved old BAS, BAV and BAT diodes again.
    Slightly different numbers but they were listed under SOT-523 which
    looks the same to me as SC-75, or SOT-416 for that matter.

    Is there a somewhat official site that has a compatibility table like
    the ones for watch batteries?
  2. Rich Grise

    Rich Grise Guest

    I don't know if there's anything "official", but just for S&G I did:

    and got "about 98,300" hits.

    Some of them look promising, especially if you know what you're looking
    for. I didn't see a(an?) "SC-75", but we don't do other people's homework
    here anyway. ;-)

  3. DJ Delorie

    DJ Delorie Guest

    You know, if any student loves electronics so much that they refer to
    "the beloved old" *anything*, maybe we should encourage them? :)
  4. Guest

    Not quite sure what you are babbling about, but if your question is
    about size of package only try this company that sells dummy components
    for assemblers to practise on. they have just about every package
    available in the industry in their catalog with drawing specs.
  5. Joerg,
    I came to tag new cases used in a layout with the manufacturer
    and its internal reference number. I doubt there is an official
    compatibility table. While some cases may look identical, their
    recommended footprint, if there is any, may not be identical.

  6. Fred Bartoli

    Fred Bartoli Guest

    DJ Delorie a écrit :
    Hey, don't give them bad trick ideas!
  7. Al

    Al Guest

    At one time military standards made devices compatible. But since they
    were dropped in favor of OTS, chaos.

  8. Joerg

    Joerg Guest

    That's always been different even for the very same sizes, I got used to
    that. But it used to be that SOT23 was SOT23 was SOT23. Now they have
    three or more designators for the same package. Makes no sense.
  9. Joerg

    Joerg Guest

    Looks like they don't have the really small sizes such as SC-75 yet.
  10. Tim Wescott

    Tim Wescott Guest

    There's a business opportunity here for the enterprising component
    engineer or layout guy:

    Make the web site, slather the borders* with click-through ads for
    semiconductor companies, PCB houses, layout software, etc. Then keep it
    up to date so that everyone goes there.

    It could, if it were good enough, pay for itself.

    Particularly if it had a nice table of equivalents, plus some
    recommended pad patterns for various different PCB layout software versions.

    * Border ads don't bother me. Pop-ups make me want to shoot someone,
    but border ads are OK.


    Tim Wescott
    Wescott Design Services

    Posting from Google? See

    "Applied Control Theory for Embedded Systems" came out in April.
    See details at
  11. Joerg

    Joerg Guest

    Yes, the military has always been an order of magnitude better in
    standardization than any civilian group. The worst ought to be EDA. Lip
    service, EDIF meetings, press releases, lots of blah-blah and the result
    is total chaos. No idea why because in medical we managed to agree on
    one standard (DICOM) and it works. Despite the fact that the number of
    competitors was a whole lot larger.
  12. Joerg

    Joerg Guest

    I got plenty of hits as well but also some contradictory pages. I was
    looking for a listing that is somewhat official. When I find one I'll
    post it.
  13. Joerg

    Joerg Guest

    It most certainly would.

    Mozilla doesn't show any pop-ups. I wouldn't mind border ads either as
    long as they are professionally done without the stupid flashing colors.
  14. EdV

    EdV Guest

    You can come up with a table but wouldn't neccesarily be good for all,
    it's not simply yes or no. Best to use the recommended pad patterns
    first which are already available in the component specs and
    manufacturers have already experimented on them. PCB and component
    footprint of each design company might be different unless they follow
    the same component specs from the supplier. But in special cases when a
    special pad is required, Manufacturing can do some adjustments on
    machine and processes inorder to address the design requirement. But of
    course the price to pay for added cost in manufacturing. In my
    experience a simple 0603 had 5 different PCB footprints (on different
    models of course) but no significant impact on reliability.
  15. Guest

    Yeah it's there...look at page 14... sc-75a is same as sot416
  16. LVMarc

    LVMarc Guest

    Advise from a wise older EE lab rat," Things that are diffeent...are not
    the same."

    sounds silly ion the surface. Ususlllay this tools can explain why it
    used to work and now does not.

    Have fun

  17. Joerg

    Joerg Guest

    Yeah it's there...look at page 14... sc-75a is same as sot416

    Yes, thanks, didn't see that. Doesn't list SOT-523 along with it though
    which is the size designator Diodes Inc. seems to prefer. From the
    datasheet of their MMBT3904T it looks the same as SOT-416 and SC-75:

    Anyway, thanks for that link. I've printed out page 14 for guidance and
    will add some other size designators to it.
  18. Guest

    I only provided you with their small 6mb catalog. It's probably in
    their 15MB catalog...
  19. Joerg

    Joerg Guest

    I only provided you with their small 6mb catalog. It's probably in
    their 15MB catalog...

    Well, I just created a separate SOT523 model in my CAD. Don't make no
    sense but at least then it can't be wrong :)
  20. tlbs101

    tlbs101 Guest

    Try: JEDEC.ORG
    As far as I know they are the standards organization for all packaging.

    Go to the "Free Standards" area. You'll have to register but it's
    free. (You don't need to be a paying member of the org to look at the

    Tom P.
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