KB: Understand Spice models supported in Altium

Solution Details

Largely, there are two main SPICE versions commonly available, SPICE2 and SPICE3, while below is a more elaborate breakdown: 

• SPICE3 (Berkeley): Spice 3F5 being the final version

• XSPICE (Georgia Tech): Extension based on SPICE3

• NGSpice (open-source): successor of Berkeley Spice 3F5, XSPICE, and Cider1B1

• LTSpice (Analog Devices): SPICE3 evolved and modified with some custom/proprietary extensions by LTC, later acquired by Analog Devices

• PSpice (MicroSim/OrCAD/Cadence): SPICE2 evolved and modified with some custom/proprietary extensions by MicroSim, later acquired by OrCAD and then by Cadence

Altium Designer supports SPICE2/3 and XSPICE.  Starting with Altium Designer 21, some support was added for both PSpice and LTspice model variants.

A device manufacturer site is the first place you may look for a model of most accurate representation, but for a simple/casual model, you may opt to create one yourself.  Prior to Altium Designer 21, it was necessary for Spice models to have the correct file extension to be recognized. New in AD21 is a *.LIB model file extension. This will recognize both .MODEL and .SUBCKT definitions in the file. The older file extensions will still be recognized. 

For a casual, analytical models, you may find Simulation Generic Components.Intlib convenient, installed by default at the path C:\ProgramData\Altium\Altium Designer {GUID}\Extensions\Mixed Simulation\Library.

Please note that all other legacy components bundled previously have been consolidated here starting in AD23.3.

But they can be downloaded independently from here if needed.


Our long-term intention is to have spice models linked upfront to a wider range of components you can save/download directly from the Manufacturer Part Search panel.

Encrypted PSpice/LTSpice/HSpice/TINA-TI models:

Models encrypted for a particular simulator can be used only in that simulator strictly. Device manufacturer encrypts its model for the purpose of protecting their IP, so it can be decrypted solely by the known designated tool.
There is a BugCrunch to have Altium work with device manufacturers to establish an equivalent encryption scheme for Altium, that you may upvote/follow to get any updates:

In the meantime, the only workaround conceivable is to find another equivalent/similar model or to negotiate with the manufacturer to obtain a decrypted model.

Unsupported model type 'A' error on LTSpice models:

According to the syntax of SPICE simulators, each instance of a primitive model must begin with some reserved Latin letter.

LTSpice is an extension of the Spice 3F5 language and has a number of additional primitive models, the description of which begins with the letter "A".

Likewise, the XSPICE extension underlying the Altium Mixed Sim simulator also has a number of primitive models with instance descriptions beginning with the letter "A".

And here is an important point - sets of additional LTSpice and Altium Mixed Sim models do not overlap. This means that there are some LTSpice models that do not exist in the Altium Mixed Sim. Among the models not implemented in the Altium Mixed Sim are OTA and SCHMITT models.  These are coded LTSpice models, which means it cannot be imported into Altium Mixed Sim as the code remains proprietary to Analog Devices, Inc.