I've been trying to learn how to use LTspice, and I'm attempting to create a model for a pFET I've been using/will use on a real board. However, since my specific transistor isn't already in LTspice's collection (probably because it's a TI part...), I'm attempting to create the model myself. I've found the standard.mos file, and while some of the arguments are easy enough to figure out (Ron, mfg, etc.), there are a few I can't figure out (Rs? Vto?).

So, my question: is there a decent reference anywhere that says what all of these arguments are? I can probably get real values from a datasheet if I know what to look for, and if not, I can make an educated guess. Currently using LTspice IV for OS X if that makes any difference.

  • \$\begingroup\$ The two you mention sound like standard spice parameters for mosfets so try googling the spice details for a mosfet. \$\endgroup\$
    – Andy aka
    Apr 11, 2014 at 23:26
  • \$\begingroup\$ Ah, you're right- I'm an idiot. Fifth result of Google search for "Rs ltspice" gives me exactly what I was looking for. Should I delete this question, or post the link I found here for future morons like myself? \$\endgroup\$ Apr 11, 2014 at 23:30
  • \$\begingroup\$ if you want to be helpful, give your own answer explaining what several of them mean. You'd be doing other folk a service immediately. \$\endgroup\$
    – Andy aka
    Apr 11, 2014 at 23:33
  • \$\begingroup\$ Too late, seems like The Photon beat me to it. \$\endgroup\$ Apr 11, 2014 at 23:36
  • \$\begingroup\$ It looks a cool answer but I'd encourage you to add how each parameter listed might affect real fet performance to a guy trying spice for the first time. I'm no expert and I'd be interested cos sometimes I have to modify parameters and I just copy n paste without any real understanding of Wtf I'm doing !! \$\endgroup\$
    – Andy aka
    Apr 11, 2014 at 23:48

1 Answer 1


In The LTSpice help file you can find this table, which I'm too lazy to figure out how to reproduce completely:

enter image description here

The table is under LTspice IV -> LTspice -> Circuit Elements -> M. MOSFET in the help file contents tab.


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