KiCad problem Help please

Discussion in 'General Electronics Chat' started by rsfoto, Jun 16, 2013.

  1. rsfoto

    Thread Starter Member

    May 14, 2013
    134
    1
    Hi,

    Having been working with the LM339 comprator in KiCad but when choosing it only one comparator appears and so far it is a Quad comprator. Now trying to make a PCB I do not find the footprint. Does that mean I have to develop it myself ?

    Thanks for any tips.
     
  2. ErnieM

    AAC Fanatic!

    Apr 24, 2011
    7,392
    1,606
    Nope, all 4 units are there. Kicad uses a feature called "parts per package" for devices just like the 339 which have 4 very similar sections, plus a common power. To allow you to place all 4 sections anywhere you want. Then you have to define which each section is.

    First, plop down 4 339 comparators. Then hover your mouse and press the E key (right click each one and select edit). In that window, top left corner you get to select which section (1 2 3 or 4) to use. You can also define the U number there.

    Be a little careful doing this: Kicad has a minor bug where it ignores the mouse and tends to pick the last section selected, meaning you may edit section A 4 times instead of the one you want to. My work around is to move (hover and hit M) each section I want to edit. Move doesn't have the sticky problem edit does, so you can be sure which section you are editing.
     
    tshuck, rsfoto and absf like this.
  3. rsfoto

    Thread Starter Member

    May 14, 2013
    134
    1
    Dear ErnieM,

    Thank you very very much. Makes life ieasier. I guess that works with all similar IC which have integrated one or more equal circuits. Right ?
     
  4. rsfoto

    Thread Starter Member

    May 14, 2013
    134
    1
    Hi,

    Thansk for the Tip but now when building the PCB I get 4 LM339 footprints.

    What do I do now ?

    Thanks
     
  5. ErnieM

    AAC Fanatic!

    Apr 24, 2011
    7,392
    1,606
    Right. Things like quad AND gates or hex inverters also are done this way.

    Something went wrong... say you call the 339 "U1" You should see the parts labeled U1A U1B U1C and U1D. If you see anything else you'll get two (or more!) parts (because that is what you've told it to do).

    Don't forget to make a new netlist in schematic editor when you make these changes, then load them in the PCB portion.

    You may also have to manually delete the "extra" ICs.
     
    rsfoto likes this.
  6. rsfoto

    Thread Starter Member

    May 14, 2013
    134
    1
    HI,

    So if I understand well the U1A is the main and if I get BCD additional I just can delete them ?

    Yes I had on every single LM339 ABCD designations.

    Will keep trying
     
  7. rsfoto

    Thread Starter Member

    May 14, 2013
    134
    1
    Hi, OK problem SOLVED :D
     
    ErnieM likes this.
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