Diode Modeling in PSpice

Discussion in 'General Electronics Chat' started by Management, Mar 10, 2009.

  1. Management

    Thread Starter Active Member

    Sep 18, 2007
    Hi there, it seems like I always as you guys for help.

    I have a question about modeling in PSpice. Sometimes I see a circuit modeled as an actual circuit, ".subckt" in model editor, or by just initializing some values off the datasheet.

    For example, I opened a diode, D1N4148, in model editor and saw this:

    .model D1N4148_1 D(Is=2.682n N=1.836 Rs=.5664 Ikf=44.17m Xti=3 Eg=1.11 Cjo=4p
    + M=.3333 Vj=.5 Fc=.5 Isr=1.565n Nr=2 Bv=100 Ibv=100u Tt=11.54n)
    * TELEFUNKEN pid=d1n4148 case=DO35
    * 91-08-20 dsq

    What I would like to know is can I use the "breakout.lib" or edit a diode like this one and just replace the values with the ones from the datasheet of the diode that I want?

    What I want to do is make a few models of diodes that don't have PSpice models already created off the vendors website.

    I'd like to find the easiest and quickest way to do this.

    Ideally, I would like to model some Schottky Diodes. Anyone know of any of those diodes that can rectify a 100V-500V peak AC signal? Ones that can maybe do both or just 250V and 500V.

    I'd like to simulate those diodes in PSpice.

    I know I just rambled but any help would be greatly appreciated.
  2. n9352527

    AAC Fanatic!

    Oct 14, 2005
    The parameters in SPICE models do not usually correspond to the parameters listed in datasheets. To create a SPICE model, for example a diode, you need to extract the characteristics of the actual device and translate that to the SPICE model parameters. It is possible to do this process from the parameters found in the datasheet, but it won't be as accurate over all the operating range of the device.

    For further information try searching for spice parameter/model extraction.

    If you really are interested in this, download the SPICE manual and look for the diode model equation. You will find how SPICE does its calculations and use the model parameters. It is somewhat easier to reverse engineer the equations to arrive at a limited range models or decide on a best strategy to extract a SPICE model from an actual device.