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Problem with Importing Varistor PSPICE Model

Hi all,


I am trying to simulate the varistor from LittelFuse - V275LA20A. The manufacturer gives  a library of PSPICE models for all different kinds of varistors that they manufacture. The PSPICE files contains two .SUBCKT statements. I have read in the forum that Multisim can only process one such statements. Anyhow, the model that I am using does not produce valid simulation data, i.e. the voltage is not being clamped when it should be. I am attaching the PSPICE files for your review. Any help would be greatly appreciated.





Viktar Tatsiankou

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Message 1 of 7

Hi Viktar,


Copy and paste the following line to the top of the model:


X1 1 2 MOV PARAMS: T={1+TOL/100} L=12nH C=450pF a1=521.1 a2=32.01 a3=-7.201e-5 a4=0.2262 a5=9.738 a6=15.41E-3 a7=4E-4

If you think of programming the part above is the main part of the code, the line starting with "X1" is a call command and it's calling another model called "Mov" and  Multisim supports this.  The attached file is a modified model.

Tien P.

National Instruments
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thank you for your repply. However, I still cannot simulate the clipping action of the varistor with the modified model. Even under low voltages it lets the current through, which makes no sense. I am attaching the multisim file for your review. Am I doing something wrong?

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Message 3 of 7

FYI, the varistor should clip everything beyond 275V.

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Message 4 of 7

I tested this model using other SPICE simulators and all are giving the same result as Multisim.  It looks like this model will clip at 600V.

Tien P.

National Instruments
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Message 5 of 7

Good evening Gentlmen. I too am working on this same exact Varistor from Littlefuse. The multisim model looks accurate but I am trying to graph the IV curve of this same model in Multisim. With current being my X-axis ranging from 10 uA to 1mA of current, and my Voltage being my Y-axis ranging from 100 to 600 Volts. I have a picture attached to this comment of what I am trying to resemble for this Varistor. Any help or assistance would be great on how to plot this. Thank YouIV Curve.jpg

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Message 6 of 7

Hi Tien_P, Smiley Happy


I also have the same problem. I want to import a PSPICE-Model from Texas-Instument for a isolated IGBT gate driver UCC20520. Link: <>

But it could not be successfully importet. The problem is that, the PSPICE files contains more than one .SUBCKT statements.

I'll be very appreciated, if you could give me some tipps. Thanks so much! Smiley Happy


Kind regards,


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