What is the difference between LTspice IV MOSFET and standard SPICE MOSFET models?
Besides the standard SPICE MOSFET models, LTspice IV also includes a proprietary MOSFET model that is not implemented in other SPICE programs. It directly encapsulates the charge behavior of the vertical double diffused MOS transistor. This allows a power device to be modeled with an intrinsic VDMOS device LTspice instead of a subcircuit as in other SPICE programs. See models definition for details.
Can I add my own MOSFET models?
Yes, you can add your own model in the
C:\Program Files\LTC\LTspiceIV\lib\cmp\standard.mos file. This file is only for devices defined with a .model statement, not as subcircuits. If you want to use a subcircuit, follow the following steps:
Change the "Prefix" attribute of the component instance of the symbol to be an 'X'. Don't change the symbol, just the instances of the symbol as a component on a schematic. You can access this attribute by holding down the control key and right clicking on the body of the component.
Edit the "Value" attribute of the component to coincide with the name of the subcircuit you wish to use.
Add a SPICE directive on the schematic such as ".inc filename" where filename is the name of the file containing the definition of the subcircuit. Note that this must be the complete name with any file extension and Windows Explorer defaults to not showing the file extension. So you if you have a file called "mylib.sub.txt", which you can edit/view in notepad, and Windows Explorer shows you the file exists as "mylib.sub" The SPICE directive to include this file is ".inc mylib.sub.txt" If you used, ".inc mylib.sub" you will get an error message that that file can't be found.
Is there a tool for generating native LTspice VDMOS MOSFET models instead of subcircuits?
Yes! Hendrik Jan Zwerver developed a free VDMOS tool that is distributed from the Files section of the independent users’ group http://groups.yahoo.com/group/LTspice.
Who is Hendrik Jan Zwerver?
The guy on the right: