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ECL logic SPICE models

Discussion in 'Electronic Design' started by Joerg, Sep 10, 2009.

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  1. Joerg

    Joerg Guest

    Gentlemen,

    Does anyone know of a source for SPICE models of ECL gates?
    Unfortunately ON Semi only supplies IBIS models :-(

    I know, I know, much of this will fall under trade secrets or NDAs and
    can't be shared. Just wondering why some companies seem reluctant to
    share this stuff. Makes no sense since providing models can only boost
    sales. No, not the models some of you might think about ... :)

    Alternatively, is there a recipe about how to boil one out of an IBIS
    model file?
     
  2. Charlie E.

    Charlie E. Guest

    Hi Jeorge,
    Unfortunately, while PSpice has ECL models, they use the PSpice
    digital simulation models that were propriietary to PSpice...

    Charlie
     
  3. Joerg

    Joerg Guest

    Dang, I thought so :-(
     
  4. Joerg

    Joerg Guest

    I have a really old license of PSpice but AFAIK those weren't very
    suitable when you wanted to "mis-use" the stuff for analog tricks.
     
  5. Joerg

    Joerg Guest

    Mostly linear behavior and change of prop delays with chip temperature.
    But it's nothing for a project (yet), just kicking the tires. The newer
    8GHz stuff looks very enticing but when I saw the prices I almost
    dropped my coffee cup.
     
  6. Fred Bartoli

    Fred Bartoli Guest

    John Larkin a écrit :
    DTL? (Dollar Transfer Logic)
     
  7. Joerg

    Joerg Guest


    Only? ... :)

    Problem is, with many of my designs the whole solution including burden
    (assembly, additional rigging costs, etc.) has to be lower than that.

    Made and sold for one defense project and nobody else is buying?
     
  8. Joerg

    Joerg Guest

    Ok, large scale integrated stuff is a different game. But when $30 are
    charged for a single inverter I'll do it with a few BFP620 transistors.
    ft around 65GHz, SOT23, about 50 cents in qties :)
     
  9. Joerg

    Joerg Guest

    So far bipolars have been good to me, starting with the old BFS17 in the
    80's. To this day I always keep a vial full of those on hand. Then
    faster and faster ones showed up. Only problem is that most are from
    large European companies and their sales channels are often, ahem, let's
    say sub-par.

    Take a look at some broadband stuff such as CATV amps. Many are done
    with discrete BJT, most likely for cost and 2nd-sourcing reasons. But
    yes, parasitics can get you and the layout is not at all trivial.

    That I still have to try.

    That's sometimes an order of magnitude too slow :-(
     
  10. Cheap compared to high temperature, let alone space stuff.
     
  11. Joerg

    Joerg Guest

    My last circuit for that market came in well under that. Lock, stock and
    barrel.
     
  12. Joerg

    Joerg Guest

    8GHz/20dB for under a buck? That would be my kind of device. Have a
    particular one in mind?

    One issue I found with RF devices was that you can sometimes only obtain
    small signal simulator models that aren't very helpful with pulse apps,
    plus require software that costs more than your Volkswagen. Even with
    big LDMOS parts I had that happen. One company (PolyFet) stuck out and
    provided SPICE models. So the big competitor will be left out ... sorry,
    NXP.
     
  13. Joerg

    Joerg Guest

    Those are cool. However, the ECG003 is over three bucks although the
    datasheet looks great.

    Lately I have simulated more, and then straight to layout. The one
    that's in fab right now is a white-knuckle ride because I am using a
    device in a weird way. Usually pans out though.

    What often amazes me is how close to abs max people (and sometimes app
    notes) bias RF devices. When it says 7V they bias them to 5V or 6V on
    the collector/drain. Some day a huge pulse finds its way into the input,
    almost saturates the device, then it lets go, the inductor shoots up ...
    phut.
     
  14. Joerg

    Joerg Guest

    I've seen that. But if you are a consultant and this goes into some
    aircraft you can't design like that. Even with an indemnification clause
    that can cause lots of grief should it go wrong in only one case. It's
    got to be by the book.

    All they really offer in many cases is a set of S-parameters. Since I
    design a lot of pulse circuitry I almost do a rain dance every time
    there is just a snippet of SPICE data.
     
  15. Joerg

    Joerg Guest

    That would be very kind.

    However, except for super large transmitter devices (and sometimes even
    then) the S-parameters have been measured under small signal conditions.
    Doesn't help much when pulsing them hard, then you are back to what John
    said, experiments on the lab bench. Got one of those coming up. I am
    going to do the first run with tubes again to see if the concept pans
    out, in order not to have stuff blow up in my face. It's really nice to
    know that one can still buy the mil version of the 6146 tube, at
    affordable prices. So far I haven't blown one though, only tired out a pair.
     
  16. Joerg

    Joerg Guest

    Thanks. I assume you mean this link:

    http://www.analog-innovations.com/SED/CreateS-ParameterSUBCKTinPSpice.pdf

    Now I have to learn QuickBasic, whatever that is ;-)
     
  17. Joerg

    Joerg Guest

    Unless I understand something wrong the first three are for extracting
    S-parameters from SPICE or PROBE (Orcad's version of SPICE).

    But maybe I'll read them again and some more elucidation will come :)
     
  18. Joerg

    Joerg Guest

    Ok, true, I was lazy here. Thought about some SW-routine where you slap
    the datasheet on a scanner, press magic button, out comes SPICE
    sub-circuit :)))
     
  19. Joerg

    Joerg Guest

    I know :)

    Right now I don't need to convert though because I just went over to
    manufacturers who furnish SPICE models. But if we really need to and
    it's crunch time I might take you up on that, or a client of mine would.

    If you and your son-in-law (the computer guy) get together and write a
    program that does this you could probably sell it to numerous
    manufacturers. Every time a guy like me walks away because they don't
    have SPICE models that means serious money is being left on the table.
    Once the BOM is done and done, it takes a major earth-shattering event
    to change it. Or very painful price cuts. I had sales reps almost in
    tears when they realized they shoulda ...
     
  20. Joerg

    Joerg Guest

    Mostly I just press on, eye-ball the rough L and C values, go into the
    garage and see if I have enough suitable variable capacitor for a test.
    Then it's off to the plumber's place for some copper tubing, to make the
    coils. At Home Depot that's now called "plomeria".

    I've had a similar event with a potential client a long time ago.
    Proposed an unorthodox solution that seemed to be "too simple" for them,
    not academic enough. They turned me down. A few years later this company
    was at the financial end of the rope and went belly up. The sad thing is
    that my solution would have potentially saved them, along with about two
    dozen jobs :-(
     
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