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Discussion in 'Electronic Design' started by David Moreno, Jun 9, 2004.

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  1. David Moreno

    David Moreno Guest

    Hi!

    I'm new to LTSpice and I'm trying to put a BF998 Transistor
    model taken directly from Philips. I've followed the instructions
    and created a new symbol for my transistor, put into the schematic
    and changed the value field to point to the name of my subcircuit.

    I've also included the model in the spice file. But when I try
    to run the simulation it gives me this error: "Can't find
    definition of model "C", and the path to the model is right.

    Any one can help me ?, Thanks !

    BF998.spice model
    ------------------------------------------------------------
    * BF998 SPICE MODEL OCTOBER 1993 PHILIPS SEMICONDUCTORS
    * ENVELOPE SOT143
    * 1.: SOURCE; 2.: DRAIN; 3.: GATE 2; 4.: GATE 1;
    ..SUBCKT BF998 1 2 3 4
    L10 1 10 L=0.12N
    L20 2 20 L=0.12N
    L30 3 30 L=0.12N
    L40 4 40 L=0.12N
    L11 10 11 L=1.20N
    L21 20 21 L=1.20N
    L31 30 31 L=1.20N
    L41 40 41 L=1.20N
    C13 10 30 C=0.085P
    C14 10 40 C=0.085P
    C21 10 20 C=0.017P
    C23 20 30 C=0.085P
    C24 20 40 C=0.005P
    D11 42 11 ZENER
    D12 42 41 ZENER
    D21 32 11 ZENER
    D22 32 31 ZENER
    RS 10 12 R=100
    MOS1 61 41 11 12 GATE1 L=1.1E-6 W=1150E-6
    MOS2 21 31 61 12 GATE2 L=2.0E-6 W=1150E-6

    ..MODEL ZENER D BV=10 CJO=1.2E-12 RS=10

    ..MODEL GATE1
    + NMOS LEVEL=3 UO=600 VTO=-0.250 NFS=300E9 TOX=42E-9
    + NSUB=3E15 VMAX=140E3 RS=2.0 RD=2.0 XJ=200E-9 THETA=0.11
    + ETA=0.06 KAPPA=2 LD=0.1E-6
    + CGSO=0.3E-9 CGDO=0.3E-9 CBD=0.5E-12 CBS=0.5E-12

    ..MODEL GATE2
    + NMOS LEVEL=3 UO=600 VTO=-0.250 NFS=300E9 TOX=42E-9
    + NSUB=3E15 VMAX=100E3 RS=2.0 RD=2.0 XJ=200E-9 THETA=0.11
    + ETA=0.06 KAPPA=2 LD=0.1E-6
    + CGSO=0.3E-9 CGDO=0.3E-9 CBD=0.5E-12 CBS=0.5E-12

    ..ENDS BF998

    -----------------------------------------------------------------------------



    SPICE NETLIST
    ------------------------------------------

    * E:\ALIENFILES\electronica\buffer para altas frecuencias\BF998 spiceLT.asc
    V1 Ui 0 SINE(2.5V 2.5 100E3)
    V2 Uo 0 5
    R1 N001 0 1k
    X§M1 N001 Uo Ui Ui bf998
    ..tran 10u
    ..inc E:\alienfiles\electronica\spice\bf998.spice
    ..backanno
    ..end
     
  2. Jeroen

    Jeroen Guest

    at Yahoo.com there's a group devoted to LTSpice.
     
  3. ----- Original Message -----
    From: "David Moreno" <>
    Newsgroups: sci.electronics.design
    Sent: Wednesday, June 09, 2004 1:34 PM
    Subject: LTSpice

    Hello David,
    I have uploaded an example circuit to the Yahoo group with four
    different Dual-Gate-Mosfets including the BF998.

    The files can be downloaded from the file's section of this group.
    Files->Lib->Dual-Gate-Mosfet

    The address of the LTSPICE user's group is
    http://groups.yahoo.com/group/LTspice

    Put these three files into one working directory and then run the
    schematic(.asc) with LTSPICE.

    If you take a look to the symbol file, then you will know one way
    how to use subcircuits in LTSPICE.

    There are hundreds of LTSPICE circuit files in file's section of
    this group.

    Best Regards,
    Helmut

    PS: If you have problems to access this Yahoo group for any reason,
    then send me your e-mail address and I will send you the files directly.
     
  4. David Moreno

    David Moreno Guest

    Hi
    Thanks !
    I've joined the group, btw I finally managed to solve the problem,
    I've only to add the units and remove the 'L=' and 'C=', the model
    worked well.

    Un saludo.
     
  5. Do you really need to model this as a subckt with such tiny paractics
    when you're only dealing with an input signal of 100Khz??
    Just curious...
     
  6. David Moreno

    David Moreno Guest

    Hi!
    Hehe, It may come higher, 100MHz or so =).
    As the cat =D
     
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