Spice Simulation Models Download Repository

[muriungi254]

Hi, I am having challenges especially in dealing with SPICE Simulation Models. Do you have a one-fit-4-all repository or a platform with most of the SPICE Models (*.mdl) can be found? A very nice example is the .mdl model for 2n7008. I have tried SnapEDA, Ultra Librarian, SemacSys, and other private sources but it is not enough. I know this is a difficult challenge, but based on the community experience, I guess you can be of help. Thanks and cheers!

[CGBenner]

@jorge_garcia @RichardHammerl Hey guys... any thoughts on this one?

[muriungi254]

Thanks @CGBenner for the assistance by personally doing a follow-up.

[jorge_garcia]

Hi @muriungi254,

I hope you're doing well. Unfortunately, we don't have such a repository though I agree it would be helpful.

I'll log this as a feature request. For now, we unfortunately don't have a better solution. One thing to note, don't let the file extension dissuade you, as long as model is a pure SPICE model it should work. You'll just have to modify the file extension.

Let me know if there's anything else I can do for you.

Best Regards,

[muriungi254]

Hi @jorge.garcia,

Thank you for your response although I may have missed something or not really understood what you mean by saying "One thing to note, don't let the file extension dissuade you, as long as model is a pure SPICE model it should work. You'll just have to modify the file extension."

Maybe to clarify my question: What happens if you "MUST" simulate a specific aspect of the circuit and you can't find the spice model? What has been the walk around especially previously with EAGLE?

[jorge_garcia]

Hi @muriungi254 ,

That's a deep question. If a spice model is not available, you could try to substitute the component with some equivalent model, this can be useful in simple simulations but it won't give you the accuracy of a manufacturer's SPICE model.

Generally, most manufacturers provide SPICE models in some format. With some adjustments they can usually be made to work. Keep in mind that SPICE simulation is really geared towards analog circuitry, if you are trying to simulate something like a microcontroller SPICE isn't really suitable for that.

If you find a manufacturer's model for your part post it and let's see if we can make it work.

Best Regards,

[muriungi254]

Hi @jorge.garcia,

Thanks for the response. I am building capacity in a fellowship program sponsored by Autodesk Foundation which demands all the fellows to use Autodesk Fusion 360 for their design work and simulations; that's why the deep followup with concepts.

In the meantime, I will engage you on a private chat so that I can share more details. Otherwise, thank you very much for the guidance. I will be sharing more info here also.

[holger.vogt]

You may have a look at the Model and model parameter collections for ngspice .

[muriungi254]

Hi @holger.vogt,

This is really helpful. Thank you very much.

[muriungi254]

Hi @holger.vogt,

Do you have a mechanism to convert .lib to .lrb library file format so that they are compatible in Fusion 360?

[holger.vogt]

Unfortunately not.

I even do not have Fusion360 available, have been doing my tests with Eagle.

Isn't the move from *.lib to *.lrb just a renaming of the model parameter file? Or is some re-formatting required?

[holger.vogt]

As far as I understand, *.lbr files contain symbols and footprints, the ngspice *.lib files contain ngspice models. You will need both for a specific device, when you want to simulate in addition to schematic entry and PCB layout, there is no way to convert one to the other.

For sure spice *.lib files don't contain any information on symbols and footprints. I am not sure about *.lbr files, but I guess they do not contain any ngspice models.

[RichardHammerl]

Hi @muriungi254 

I guess, @holger.vogt is right. This is what Jorge meant. Rename the file and try.  🙂 

Regards,

[muriungi254]

Hi @holger.vogt,

Let me work on renaming and testing if it works out. Thank you for the recommendation.

[muriungi254]

Based on this explanation, the initial explanation becomes invalid.

While in Fusion 360 and try to upload and offline downloaded library, it requests a *.lbr and not a *.lib. @holger.vogt, let me know if what you meant to change the available *.lib to *.lbr since it is compatible format.

Additionally, you can clarify whether the above works since based on your explanation, it's seems as if both .lib and .lbr have different contents.

[muriungi254]

Hi @RichardHammerl,

Kindly check a follow-up explanation that @holger.vogt shared regarding the differences on both files.

[muriungi254]

@jorge_garcia, kindly clarify the compatibility issues with both .lib and .lbr as highlighted by @holger.vogt. Thank you.

[jorge_garcia]

Hi @muriungi254,

I hope this message finds you well. Let's clarify

1. lbr - This extension is used to define a Fusion 360/EAGLE compatible library it's completely separate from the SPICE discussion. It's possible that a simulator uses the same extension, but I'm not aware of the top of my head.

2. mdl - This is the extension our built in SPICE engine (ngspice) uses for models.  The file consist purely of SPICE syntax. Proprietary SPICE simulators support base SPICE syntax but build additional syntax on top of it which creates problems when you try to use models made for PSpice, TINA, etc. within our simulator. You basically have to replace those proprietary parts with plain SPICE.

3. lib, cir, asc, etc. - These are all different extensions used by various SPICE simulators. When you download a component model from a manufacturer in PSpice, TINA or whatever format the first thing to do is open it in a text editor and verify that the syntax looks like SPICE. If it does, save the file and change it's extension to mdl. Try mapping it to a device in the Device editor if there is no complaint then awesome you are done. If there is an error then you are going to have to start sifting through the file replacing the offending syntax with plain SPICE syntax (this requires knowledge of SPICE and is not an easy thing to do if you are new to it).

Ideally we would want to be able to use those models as is and @holger.vogt knows as well as we do that the latest versions of ngspice can actually use the files as is but so far we have not updated the SPICE engine to use a newer version it's on our to do list but we are addressing larger tasks at the moment.

Let me know if you continue to run into problems.

Best Regards,