Help with spectrespp

Discussion in 'Cadence' started by mayank, Dec 1, 2005.

  1. mayank

    mayank Guest

    Hi Guys,

    I am at the end of my wits with spectrespp. I am doing everything in
    the textbook fashion and yet spectre is giving weird results. If you
    have had the same problem before or know a solution to this please
    please help. Gory details are given below but the essence is that
    ..measure is not being translated correctly. Also I could not find exact
    documentation of the "cross" function in the mdlref.pdf of spectre
    documentation.
    My sincere thanks and best regards
    Mayank

    ----------------
    I have an hspice file that has measure statements like this
    ----------------

    ..meas dc Vtsat find V(g) when i(mx1)='600e-7'
    ..meas dc Idsat find i(mx1) when V(g)='1.0'

    -------------------------
    hspice runs perfectly and generated a ms0 file that looks like this
    -------------------------
    [mayankg: Remove]$ more NT_Vt.ms0
    $DATA1 SOURCE='HSPICE' VERSION='U-2003.09 '
    ..TITLE '*'
    vtsat idsat temper alter#
    0.4820 5.769e-04 25.0000 1.0000
    -------------------------
    Now when I used spectrespp on the spice file spice
    [mayankg: Remove]$ spectrespp NT_Vt.sp
    It creates a mdl file corresponding to the measurement statements. The
    mld file looks like this
    [mayankg: Remove]$ more NT_Vt.mdl
    -------------------------
    alias measurement dcrun {
    export real vtsat, idsat
    run dc
    vtsat=V(g)@cross(sig=I(mx1:1)-600e-7)
    idsat=I(mx1:1)@cross(sig=V(g)-1.0)
    }
    foreach temp from {25.0 } {
    foreach vg:dc from swp( start=0.0, stop=1.00, step=xvstep ) {
    run dcrun as dcrun1
    }
    }
    -------------------------
    The corresponding .measure file that is created has only NaN instead of
    number!!!
    Please why should something like this happen??? Not to me. Plz help.
    -------------------------
    [mayankg: Remove]$ more NT_Vt.measure
    -------------------------
    Exported variables from PSF results directory: NT_Vt.raw
    Swept Measurements :
    Measurement Name : dcrun1

    Analysis Type : dc
    idsat temp @ 25 vg:dc @ 0 = NaN
    idsat temp @ 25 vg:dc @ 0.005 = NaN
    ....................
    idsat temp @ 25 vg:dc @ 0.995 = NaN
    idsat temp @ 25 vg:dc @ 1 = NaN

    vtsat temp @ 25 vg:dc @ 0 = NaN
    vtsat temp @ 25 vg:dc @ 0.005 = NaN
    ....................
    vtsat temp @ 25 vg:dc @ 0.99 = NaN
    vtsat temp @ 25 vg:dc @ 0.995 = NaN
    vtsat temp @ 25 vg:dc @ 1 = NaN
     
    mayank, Dec 1, 2005
    #1
  2. If you're using IC5141, I'd recommend using:

    spectre +csfe yourHspiceNetlist

    If using MMSIM60, +csfe is enabled by default. The new front end
    can natively parse SPICE netlists rather than having to go via spp.

    I'm afraid I'm short of time at the moment, so can't delve further into this.

    Andrew.
     
    Andrew Beckett, Dec 1, 2005
    #2
  3. mayank

    mayank Guest

    Thanks so much Andrew!!! A part of my nightmare is elevated :D

    spectre +csfe works perfectly..

    -mayank
    ps: if this was on google.answers I should have paid you a million buck
     
    mayank, Dec 2, 2005
    #3
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