Installing LTSpice model for IRL540?

Discussion in 'General Electronics Chat' started by spinnaker, Dec 13, 2015.

  1. spinnaker

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    I always thought that LTSpice required a sym file and a lib file?

    I think I found a spice model here.
    http://www.vishay.com/mosfets/related/

    But I am not seeing a sym file. s there a difference between spice and tspice? If not, how do I get a model installed for the IRL540?
     
  2. MikeML

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    If the pin order in the downloaded model matches the generic LTSpice NMOS symbol, then you use the generic symbol with the downloaded model.
     
  3. spinnaker

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    But the IRL540 has some special characteristics being it is a "logic level" mosfet. Is there a generic LTSpice model that fits those specs? If so how do I find it?
     
  4. spinnaker

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    Granted I am far, far from an LTSpice expert. I only dabble with very simple circuits. Does LTSpice reflect real word specifications of components?
     
  5. spinnaker

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    International Rectifier gets even more confusing. They have something called an SPI file for spice.

    http://www.irf.com/models
     
  6. ronv

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    Well kind of real world for some or most stuff, but it will let you run components way out of spec. So just because it runs doesn't mean you can ignore the datasheet and expect the real world circuit to work.
    Being lazy what I usually do with FETs is pick one out of the standard library with similar specs for Rds on, gate charge and logic level if it is one. So in your case I would just use the IRLR3802.
     
  7. spinnaker

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    Thanks for the tip on IRLR3802. How do you find it in LTSpice? Or do I need to add it?
     
  8. MikeML

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    Take the attached file, testIRL540.zip.txt, down-load it, and then rename it to be just testIRL540.zip. You should then be able to extract the files therein into a clean subdirectory. If you click on 540test.asc, it should start LTSpice and run the sim. Plot the drain voltage and drain current.

    This is what you should see:

    540.gif

    To get the sim to run, I had to download the sihf540-p.lib file from here.
    It is html, so I had to use an editor to strip the html to make it a pure text file. That is where the .sub file inside the zip file came from.

    I then used my own NMOS symbol (also in the zip file), and I edited the "Spice model" attribute to match the name in the .subckt part of the .sub file...
     
    Last edited: Dec 13, 2015
    cmartinez likes this.
  9. ronv

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    If you click on the component tool then select NMOS and add it to your schematic. Then you can right click the part in the schematic and it will show you a list of FETs.
    But having said that, I led you astray. The IRL530 would be closer.
     
  10. MikeML

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    Almost the same model as before.
     
  11. Bordodynov

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    .model IRLR3802 VDMOS(Rg=3 Vto=1.39 Rd=0.16188m Rs=0.5m Rb=5.75m Kp=56 Cgdmax=2.1n Cgdmin=.5n Cgs=2n Cjo=2.5n Is=2.7p mfg=International_Rectifier Vds=12 Ron=6.5m Qg=27n)
     
  12. spinnaker

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    Thanks for figuring that all out. I will keep playing with it but it is not plotting anything when I run the simulation. I see the circuit but no plot after running the sim.
     
  13. spinnaker

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    Got it. Thanks for the help.
     
  14. MikeML

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    Two steps: 1. Run the sim.
    2. Left-Click on a node to plot the voltage at that node. Left-Click on a component or a pin to plot current. Alt-Left-click to plot the power dissipation in a component.
     
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