how to use pruneDevice for pmos4

Discussion in 'Cadence' started by Ck seok, Dec 1, 2003.

  1. Ck seok

    Ck seok Guest

    In divaLVS rule file, I added "pruneDevice(MOS ("pmos4" "nmos4")) to prune
    dummy transistors.

    I mean that dummy transistors are transistors with D, G and S connected
    altogether.

    "Mos4"s with drain, source, gate and bulk connected altogether were pruned.
    However, mos with only drain, source and gate connected altogether was not
    pruned.

    How can I prune those dummy transistors?

    One more thing. Are there any other reasons we use dummy
    transistors except "etching issue"?
     
    Ck seok, Dec 1, 2003
    #1
  2. Ck seok

    G Vandevalk Guest

    pruneDevice can omly be used with devices that have all nodes shorted
    together.

    MOSFETS are often used as capacitors (i.e. S & D shorted, G to BULK is
    the capacitor.)
    or simply as TURNED OFF MOSFETS (i.e. G shorted to BULK) Both of these
    devices are
    often treated by circuit designer as being something other than MOSFETS.

    The S/D shorted mosfets can be extrated as separate devices. (do not use
    the physical keyword
    and code both cases as device lines to separate devices.

    Also an odd formed mosfet can be created by a Y shaped gate. This should
    be avoided or declared evil.

    YMMY

    -- Gerry
     
    G Vandevalk, Dec 1, 2003
    #2
  3. Ck seok

    Ethan Dawe Guest

    Dummy devices may also be added to be used as a "spare." During a metal spin
    it could be rewired to nearby parrallel devices.

    Ethan
     
    Ethan Dawe, Dec 3, 2003
    #3
Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Similar Threads

  1. how to use "adc_dnl_8bit" for DNL simulation?

  2. Models for nmos4 & pmos4, and finding files with specific contents

  3. How to use SKILL to change all pin names for a cell layout library

  4. Change 'config in use' into 'use named config' using API

  5. For those who use PDFs as a shop drawing, what interface do you use to get to them?

  6. How to use Block attached attributes for labeling ?

  7. How to use Entity Data for labeling ?

  8. How I can use AutoCAD standard dialog for database ?

Loading...