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Pspice MOSFET models

Discussion in 'CAD' started by Subhajit Sen, May 26, 2004.

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  1. Subhajit Sen

    Subhajit Sen Guest

    I am experimenting with Pspice (v.10) for analog VLSI
    circuit design using MOSFET models available from
    the web(from modeling companies/foundries etc.)
    and some old level-3 HSPICE level-3
    models. I am aware than Pspice does
    not support 'binning' that is characteristic
    of VLSI MOSFET models but prepared to do the necessary
    work-arounds for this (write separate models etc.).

    So far I have been able to get Pspice to simulate
    by modifying the models file e.g. comment out
    parameters e.g. ACM (which specifices diode cap.)
    etc. However, I am not getting expected results
    e.g. the gain values I am computing differ from
    what Pspice gives.

    My question is: has anybody
    had successful experience in using Pspice as
    with models published in the web (from foundries,
    modelling companies etc.) for
    analog VLSI design and obtained consistent results.
    Also does anybody know of of foundry supplied models
    that work well with Pspice?

    Regards,
    Subhajit
     
  2. Jim Thompson

    Jim Thompson Guest

    (1) Foundry-provided models work just fine with PSpice and correlate
    virtually exactly with simulations on HSpice, Cadence, etc.,
    PROVIDED...

    (2) Use a high level model. Level=3 is amateur land.

    (3) If you simulate a different gain than what you calculate, your
    calculation is inaccurate.

    ...Jim Thompson
     
  3. iQbal

    iQbal Guest

    I had recently used Orcad PSpice modeller to perform level 49
    simulations that matched exaclty as HSPICE.

    What you need to do is convert the foundry data using PSPICE model
    convertor

    iQbal
     
  4. Subhajit Sen

    Subhajit Sen Guest

    Is the model converter part of Orcad or Pspice GUI's or a
    separate utility? Is it part of model editor? How does one access it?
    Also is there support for the various BSIM models going upto BSIM4.x?

    (Also to Jim's comment that Level-3 is "amateur land": that
    may well be the case but one of my tests for a good simulator when I
    try out
    a new one is to see if it "works" with levels 1-3 IC MOS models.
    Isn't it true that these are some of the first IC MOS models developed
    for Berkeley Spice versions around which most modern Spice simulators
    (including Pspice) are built?
    Also if you are a just begining learning analog IC design and use some
    standard
    text books such as Gray & Meyer, Laker & Sansen, Johns & Martin the
    examples given are mostly levels 1-3.)

    Subhajit
     
  5. Jim Thompson

    Jim Thompson Guest

    It was posted for awhile on the Cadence site, then withdrawn due to
    bugs... likewise was on my site for awhile. Brian Hirasuna, of
    Cadence, promised it will be refined later this year.
    Textbooks are rarely up-to-date. Levels 1-3 are used in textbooks
    since the equations are simple-minded... higher level models are for
    computers ;-)

    I shared the podium with Willy Sansen in 1987 in Melbourne, Australia,
    at the Royal Melbourne Institute of Technology. He taught CMOS analog
    design, I taught bipolar.

    Or download "Binning.exe" from my website (written by my son Aaron).

    See "HSpice2PSpiceNewEdit.pdf" on the S.E.D/Schematics Page of my
    website.

    You **should not** be seeing differences between simulations done with
    PSpice and HSpice.

    I have **1522** folders of foundry-provided Spice models that work
    quite nicely with PSpice ;-)

    (Before anyone asks... NO, I CAN NOT SHARE THEM... I am bound by
    NDAs.)

    ...Jim Thompson
     
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