LTSPICE Darlington model problem

Discussion in 'General Electronics Chat' started by Veracohr, Oct 21, 2014.

  1. Veracohr

    Thread Starter Well-Known Member

    Jan 3, 2011
    551
    76
    Has anyone used a subcircuit model of a Darlington transistor in LTSPICE? I'm trying to incorporate the MPSA14 in a simulation because I have some, but it keeps saying the definition can't be found. This is the model I found:

    Code (Text):
    1.  
    2. * MPSA14 Darlington Transistor "macromodel" subcircuit
    3. * created using Parts release 8.1 on 01/07/98 at 09:47
    4. * Parts is an OrCAD product.
    5. *
    6. * connections:    Collector
    7. *                 |  Base
    8. *                 |  |  Emitter
    9. *                 |  |  |
    10. .SUBCKT MPSA14    1  2  3
    11. *
    12. Q1 1 2 4 Q1model
    13. Q2 1 4 3 Q2model 2.873
    14. D1 3 1 Dmodel
    15. R1 2 4 200.0E6
    16. R2 4 3 200.0E6
    17. .MODEL Dmodel D
    18. + IS=10.00E-15 RS=1.000E-3 N=1 XTI=3
    19. +  CJO=10.00E-21 VJ=1 M=.5 FC=.5
    20. .MODEL Q1model NPN
    21. +  IS=53.12E-15 BF=540.5 NF=1 VAF=100
    22. +  IKF=.3345 ISE=77.22E-15 NE=1.366 BR=.6588
    23. +  NR=1 VAR=100 IKR=2.639 ISC=907.4E-15
    24. +  NC=2.069 RB=1.610
    25. +  RE=0 RC=0 EG=1.110
    26. +  CJE=12.06E-12 VJE=.7315 MJE=.3308 TF=500.0E-12
    27. +  XTF=10 VTF=10 ITF=1 CJC=14.32E-12
    28. +  VJC=.35 MJC=.2845 XCJC=.9 FC=.5
    29. +  TR=500.0E-12
    30. .MODEL Q2model NPN
    31. +  IS=53.12E-15 BF=540.5 NF=1 VAF=100
    32. +  IKF=.3345 ISE=77.22E-15 NE=1.366 BR=.6588
    33. +  NR=1 VAR=100 IKR=2.639 ISC=907.4E-15
    34. +  NC=2.069 RB=1.610
    35. +  RE=0 RC=0 EG=1.110
    36. +  CJE=12.06E-12 VJE=.7315 MJE=.3308 TF=500.0E-12
    37. +  XTF=10 VTF=10 ITF=1 CJC=0
    38. +  VJC=.35 MJC=.2845 XCJC=.9 FC=.5
    39. +  TR=500.0E-12
    40. .ENDS
    41.  
    There was one parameter I removed, "NK" (from the NPN models), because it's not in the LTSPICE User's Guide so I thought it might not be a valid parameter for LTSPICE and that it was the problem, but it didn't help.

    I've added other subcircuit models just fine, opamp models like TL071 and NE532, but for some reason this Darlington transistor isn't working. Can anyone else use it successfully?
     
  2. ericgibbs

    AAC Fanatic!

    Jan 29, 2010
    2,503
    380
    hi,
    It works OK for me.
    Did you first open the npndarlington using the F2 pop up selection box.? then change the name to MPSA14, then add inc MPSA14.mod or sub.?
    E
     
  3. Veracohr

    Thread Starter Well-Known Member

    Jan 3, 2011
    551
    76
    I didn't previously have an npndarlington symbol, but I made one. I don't know what's wrong with it, but it was the problem. I acquired a different symbol file and it works now, thanks.
     
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