[Diode] Model for 1N4148W

Discussion in 'General Electronics Chat' started by Ziko, Jul 12, 2010.

  1. Ziko

    Thread Starter New Member

    Jul 12, 2010
    8
    0
    Hello.

    Are dealing with a simulation of a circuit through the Advanced Design System software and I have some difficulty in creating (or find) a model for the diode 1N4148W.
    This reading the datasheet of the manufacturer should be a diode and high-speed, so far so good. What causes me difficulty is that the parameters that appear on the datasheet does not correspond with what the mortgage requires.

    I hope I explained clearly enough. Sorry for my bad English.

    1000 Thanks in advance to anyone who winds past my problem.
     
  2. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Unless your design is really critical, you could use a model for a 1N4148 or 1N914 computer switching diode. You will see essentially the same performance in a simulation.

    The real challenge comes when you build the circuit, and realize all of the parasitics that you did not account for in the simulation.

    Simulations are merely a starting place.
     
  3. Ziko

    Thread Starter New Member

    Jul 12, 2010
    8
    0
    I do not think the component is critical. What I wanted but it is as close as possible to the behavior of the diode described here:

    DataSheet

    I use ADS and I do not know where to put the parameters provided by the manufacturer.

    Also, what difference exists between the diode and 1N4148 1N4148W?
    Thank you.
     
  4. Ron H

    AAC Fanatic!

    Apr 14, 2005
    7,050
    656
    From the Vishay web site:
    Code ( (Unknown Language)):
    1. * Model for Vishay diode 1N4148W-V .....
    2. * T154D Chip (not T157D)
    3. *
    4. * VISHAY Semiconductor GmbH
    5. * Hartmut Harmel, 13 July 2006
    6. *
    7. .SUBCKT 1N4148 1 2
    8. .MODEL PN D (
    9. + N=2.6
    10. + IS=0.62E-9
    11. + RS=1.07
    12. + trs1=0.0016
    13. + IKF=35.490E-3
    14. + XTI=3
    15. + CJO=0.453p
    16. + VJ=0.75
    17. + M=.0331
    18. + FC=0.5
    19. + TT=4E-9
    20. + BV=105
    21. + TBV1=0.0005
    22. + ISR=12e-9
    23. + NR=2.04
    24. + EG=1.2
    25. + IBV=0.001
    26. + KF=0
    27. + AF=1
    28. + IBV=1e-10)
    29. L1 1 3 1.0n
    30. L2 4 2 0.5n
    31. D1 3 4 PN
    32. .ENDS
    33.  
    34.  
    Note that this is a subcircuit, and includes package parasitics (L1 and L2).
     
  5. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Then why worry about it?

    The standard 1N4148/1N914 model should be adequate.

    Have you reviewed the datasheets of the two diodes?

    That is how the SPICE models are derived; by careful examination of the datasheets, and implementing the published specifications.

    SPICE models are always a compromise between real-world accuracy and speed of simulation. Your mileage will vary.

    Differences between the 1N4148 and the 1N4148W won't amount to anything, compared to the parasitics in your circuit that you will probably not take the time to model.

    SPICE gives you a starting place; a theoretically viable circuit. From that point, you build the actual circuit, and start testing to find out what wasn't modeled.

    The differences between the 1N4148 and the 1N4148W will likely be the very least of your parasitic problems.
     
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