Hi

I got a .CKT file and .lib file of photodiode and transimpedance amplifier.

I know how to make spice model from these files.

However, I want to separate transimpedance amplifier part from the .CKT file or .lib file.

Is it possible to separate?

The lib file has many raw data which are unknown to me.

 

Anything is possible if you know what you are doing. Why not post your files by uploading them to the \Temp folder. That way we are in a better position to help you. Best method is to combine the into a ".zip" file. DO NOT use any other form of compression. Thanks.

On Thu, Dec 19, 2024 at 09:00 PM, Mirza wrote:

I got a .CKT file and .lib file of photodiode and transimpedance amplifier.

I know how to make spice model from these files.

However, I want to separate transimpedance amplifier part from the .CKT file or .lib file.

Is it possible to separate?

It's impossible to say anything about your files or models, without seeing them.

 

But I will say that you probably can separate the photodiode part of the model from the amplifier part of the model.  Usually they can easily be separated.

 

By the way, filename extensions do not make any difference.  Maybe they mattered if they were made for a different simulator, but LTspice doesn't care whether it is .CKT or .LIB or .MOD or .Nonsense.

 

The lib file has many raw data which are unknown to me.

That is puzzling and I don't know what you mean.  Is the model encrypted?  If it is, then much of it would look like confusing data.  It is usually easy to tell when a model is encrypted by looking for the telltale identifiers.  Let's assume that it is not.

 

Perhaps the model uses tables, which could be extensive.

 

I am confused that you say you know how to make a SPICE model from those files, yet some of their contents are unknown.  That doesn't make much sense.

 

Andy

 

Thank you very much for your comments. Actually because of NDA with the company I received the file, I can not upload the lib file.

Can I find any example where the lib file is separated according to the components?

Thank you very much for your advice.

Because of NDA with the company I got the file, it is difficult for me to upload the file.

Can I find any example where the lib file is separated according to the components?

I am sorry for the confusion about "The lib file has many raw data which are unknown to me".

I meant I do not understand the meaning of contents o fckt or lib file.

For example, there are hundreds of lines and each lines have meaning.

By seeing these lines, I do not understand and also which lines belong to photodiode and which lines belong to transimpedance amplifier.

 

I am sorry for my poor knowledge about it.

 

 

On Sun, Dec 22, 2024 at 08:35 PM, Mirza wrote:

Can I find any example where the lib file is separated according to the components?

It would be pointless for anyone to show you an example like that.  Every circuit is unique.  "All" you need to do is identify the parts that belong to the photodiode and to the amplifier, and delete one of them.  Deleting things from the model file means literally deleting lines of text.

 

Since you can't share the model file with us, there is no way anyone here can do that for you.  The only way to tell which parts belong to the photodiode and which parts belong to the transimpedance amp, is to actually SEE it for ourselves - which we can't do.  You are on your own.  Sorry.

 

Chances are good that the photodiode part is smaller, so it might be easier to single it out.  It might be as simple as one line in the model file, or it could be dozens of related lines.

 

I meant I do not understand the meaning of contents o fckt or lib file.

For example, there are hundreds of lines and each lines have meaning.

By seeing these lines, I do not understand and also which lines belong to photodiode and which lines belong to transimpedance amplifier.

Then in that case, I think you are in trouble.  Can you find another engineer where you work who understands SPICE netlists and is covered by the NDA and can help you with this?

 

SPICE netlists are not hard to figure out.  For example, any line starting with "R" is a resistor.  "D" is a diode.  The first letter is always the key.

 

Andy

 

Also -

 

What is this .CKT file you keep talking about?

 

Presumably your SPICE model for the part is in the .LIB file, and only in the .LIB file.  If that is the case, then the .CKT file is not part of the model.  Maybe the .CKT file is something needed by PSpice or some other simulator.  LTspice doesn't need that file.

 

I'm not saying that LTspice never uses a .CKT file.  If the part's SPICE model was in the .CKT file, then that is the file LTspice needs.  It doesn't care what is the filename extension.  But because you also have a .LIB file, chances are very good that the .LIB file is the SPICE model and the .CKT file is not.

 

It would not be unheard-of to have parts of a model in both files.  Very unusual, but not impossible.

 

The best way to tell is by looking at what's inside each file.

 

Andy

 

 

Thank you very much for your help.

Chances are good that the photodiode part is smaller, so it might be easier to single it out.  It might be as simple as one line in the model file, or it could be dozens of related lines.

SPICE netlists are not hard to figure out.  For example, any line starting with "R" is a resistor.  "D" is a diode.  The first letter is always the key.