LTspice Transformer Library


  • LTspice IV is a free, high-performance, SPICE simulator software by Linear Technology which is widely used in the industry.
  • The Wurth Electronics Midcom libraries contain LTspice models for over 650 of our power transformers, including designs for lighting and metering applications, PoE and PoE+, isolated DC/DC converters, flyback and offline transformers.

Using the Library

  • Our main library, the Standard Library, provides fast, usable models that run well in LTspice. The Standard Library contains models that simulate very quickly, are very accurate and include parasitic effects.
  • We also offer a Basic Library, which provides LTspice models with a netlist that can be imported and converted into other SPICE programs. To use our models in other SPICE programs, download this library as well. Those models incorporate turns ratio, inductance and DC resistance while coupline the windings of the transformer.
  • The zip file can be downloaded and saved anywhere on the hard drive

Install the Files

  • Open the zipped folder previously downloaded.
  • It contains the folders named "ForTheSymFolder" and "ForTheSubFolder".
  • Save the symbol files (.asy extensions in the "ForTheSymFolder") in the "\sym" folder of the LTspice folder structure.
  • Next save the netlist file (.lib extensions in the "ForTheSymFolder") to the "\sub" folder in the LTspice folder structure.
  • Once the files are saved in the correct folders, they can be easily accessed from any LTspice schematic.

Note: If the LTspice program is open while moving files, close the program and reopen it to refresh.

Use the Models

  • The transformers can be added to a schematic by clicking the Component button on the toolbar after being saved in the proper folders.
  • Our basic models are named as the part number followed by "_B". These models use the basic netlist (.lib).
  • Our standard models are named as the part number. These models use the standard netlist (.lib).
  • Notice: Our libraries have been updated to maintain compatibility with an LTspice IV update on 1/30/2015 that processes the way that LTspice recognizes models. If using our version V1-x libraries, it is necessary to re-download our libraries when performing an update to your LTspice program.

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