Importing/Creating a MOSFET

Brief disclaimer: I’m no engineer and just began taking power electronics seriously a year ago. I’m not familiar with other serious simulation software beyond knowing it exists. Today is my second day with Qspice having before only used falstad.

I have a need to model a circuit with an NPN MOSFET that has no model available that I can find - the Vishay SQJQ144AER. I believe I’ve constructed an acceptable level 3 model but I’ll not be sure until I can simulate some stuff and get some measurements. While not the purpose of my post I’ll include parameters/file I’ve created now:

.model SQJQ144AER NMOS(IS=1E-6 XTI=3 EG=1.11 VAF=40 BF=160E-3 + NE=1.307 ISE=1E-12 IKF=0.5 XTB=1.5 BR=1 + NC=2 ISC=0 IKR=0 RC=1 CJC=7.6E-9 MJC=0.5 VJC=2.75 FC=0.5 + CJE=7.6E-9 MJE=0.5 VJE=2.75 TR=1E-9 TF=1E-9 ITF=1 + VTF=1 XTF=1 RB=1.3)

I’ve been following Mike Engelhardt’s recent video for “Importing 3rd Party…” as this was the most straightforward method I could find. Copying the text I’ve created for my model and pasting. This seems to have worked and I do have the fet symbol with the name that pops up for me to paste/manipulate; however I am not finding it stored in the NMOS (or any other, though I’ve not checked all) .txt that is in the installation folder. Also, I am unable to locate (should it exist) my SQJQ144AER in the Symbol & IP Browser sidebar to use in new schematics.

My concern here is that it’s not saving anywhere and is not usable - that I’m making an error importing the model. I haven’t been able to get a circuit running with it but this can just as easily be caused by my unfamiliarity with the program and not an issue with the model being uploaded. My hope is that someone here has enough experience and knowledge with the program to point out what - if any - errors I am making so as I may get to pushing the electrons where I am hoping to push them.

I’m not sure how the upload file system works here on this forum, but I am uploading a JPEG of the QSPICE schematic with the FET and the Symbol Properties sidebar as it probably contains relevant information.

Thank you for your time.

Hi Yeuph,

The problem is that those are not MOSFET parameters but bipolar transistor parameters. That is,

.model SQJQ144AER NMOS(IS=1E-6 XTI=3 EG=1.11...

would be correct had it been

.model SQJQ144AER NPN(IS=1E-6 XTI=3 EG=1.11...

But the SQJQ144AER product is defiantly a MOSFET. So the model name is in appropriate. That’s not a model of the SQJQ144AER.


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Thank you!

Back to work then.