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History of D-sub connector footprints

Discussion in 'Electronic Components' started by Joel Kolstad, Feb 6, 2006.

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  1. Joel Kolstad

    Joel Kolstad Guest

    I got to thinking the other day... does anyone know why the standard D-sub
    connectors (9 pins, 15, 25, 37, etc.) use pins that are 0.109" apart? Why
    0.109"? That's just enough that I've seen people try to use the parts on 0.1"
    spaced pads, and with enough effort I've even seen them succeed. :)

    ---Joel Kolstad
  2. Boris Mohar

    Boris Mohar Guest

    If you look carefully you will notice that 9 pin ones are 0.108" I have
    over a hundred D connectors in my library and still have to make new ones.
    There are lot of subtle variations between manufacturers.


    Boris Mohar

    Got Knock? - see:
    Viatrack Printed Circuit Designs (among other things)

    void _-void-_ in the obvious place
  3. Pete

    Pete Guest

    I'm in need of a little help in verifying the pin layout of an IRF9610.
    I downloaded the IR data sheet but it doesn't specify witch lead is
    Package is TO-220AB. From past experience with power MOS FET, with the
    front facing you, it is from left to right GDS, but I need to be sure
    because I don't want to find out that it's the other way around when it
    tries to switch 117 VAC @ half an amp.

    Thanks Pete
  4. Ross Herbert

    Ross Herbert Guest

    You can take it for granted that the pin arrangement will be G - D - S
    left to right looking at the package from the front side.

    Here is a Nelson Pass design which uses this device
    See page 6 for parts layout of pcb.
  5. Franc Zabkar

    Franc Zabkar Guest

    - Franc Zabkar
  6. I seem to remember a story that it was a drafting mistake!. The draftsman
    setting out one of the original connectors, allowed 1.3", for 13 pins.
    Forgetting that there is one less 'gap', than the pin number. This then
    gives 0.10833" per pin, which seems to be 'right'...

    Best Wishes
  7. Pete

    Pete Guest

  8. bob hoffman

    bob hoffman Guest

    These connectors were designed many years ago. .109 is 7/64".
  9. Joel Kolstad

    Joel Kolstad Guest

    Hmm... the thread regarding "Why are PCBs 62.5 mils thick?" suggests that
    "years ago" it would have been atypical to use fractions smaller than a 32nd?
    I'll keep your explanation in mind... although I'd have to say I'm almost
    wishing the bit about "the draftsman for a DB-25 mistakenly draw 1.3" end to
    end," is true, due to its more colorful quality. :)
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