APPLICATION NOTE
UnitedSiC_AN0005 – August 2019
Zhongda is a Senior Staff R&D
Engineer at United Silicon
Carbide. Experience includes SiC
device designs, product
development, and generating
SPICE models.
Learn more about power
electronic applications at
https://unitedsic.com/downloads
Using UnitedSiC SPICE
model in LTSPICE
Zhongda Li, Ph.D.
Introduction
This application note explains how to use UnitedSiC SPICE models in the
popular circuit simulator LTSPICE.
Application Note: UnitedSiC_AN0005
August 2019
2
Downloading the UnitedSiC SPICE Models
Figure 1 UnitedSiC FET Selector Web Page (https://unitedsic.com/cascodes/
)
The SPICE model file is in text format (*.txt file). Simply click the “SPICE” icon to open the SPICE
model file (text, “.txt) in the browser, as shown in Figure 1, and copy and paste into Notepad
and name the file with the part number. For example, for the part UF3C120080K4S, the SPICE
file name should be “UF3C120080K4S.txt”.
Note that you do not necessarily have to make the file extension to be “.txt”. The file extension
can to be anything, such as “lib” or “sub”, and the model will still work.
Downloading the UnitedSiC Symbol Files (*.asy) for LTSPICE
Figure 2 UnitedSiC Symbol Files (*.asy) for LTSPICE
Next download the symbol files as shown in Figure 2 and save them under the LTSPICE default
symbol folder. The folder is by default under:
C:\Users\YOUR_USER_NAME\Documents\LTspiceXVII\lib\sym
We recommend creating the “UnitedSiC” folder and copy the four .asy files into it.
Configuration of LTSPICE
Figure 3 Content of the “SPICE Options.txt” File
The “SPICE Options.txt” file contains the options to set numerical accuracy of the SPICE
simulator and can be downloaded from UnitedSiC website. We recommend the values shown
in Figure 3 based on the optimized trade-off between simulation accuracy and ease of
convergence.
Once this file is downloaded, you can use the SPICE command “.inc” to include the file in your
circuit file. We will show how to do this in later section.