can't find definition of model 'MBRA340T3G' in LTspice?

eetech00

Joined Jun 8, 2013
3,154
Thank you very much for your help.
the diode name was correct ,but not preceded by D? is that what makes the difference?I did not know that we must enter D before the name of the diode and wonder if it is the same for Transistors too
The diode model name was not correct. It needs to be the same as the name assigned by the author of the spice model.
If you view the content of MBRA340T3G.LIB.LIB file you will see that the name used for the diode model is prefixed with a "D".
The name is the text following the .MODEL statement, and looks like this:

.MODEL Dmbra340 d

There is no standard naming convention for spice models or devices and the name may or may not be the same as the real part. When an error is displayed like the one in post #1, experience has shown that the correct .model name (or .subckt name) should be the first thing verified.
 

Thread Starter

TarikElec

Joined Oct 17, 2019
80
The diode model name was not correct. It needs to be the same as the name assigned by the author of the spice model.
If you view the content of MBRA340T3G.LIB.LIB file you will see that the name used for the diode model is prefixed with a "D".
The name is the text following the .MODEL statement, and looks like this:

.MODEL Dmbra340 d

There is no standard naming convention for spice models or devices and the name may or may not be the same as the real part. When an error is displayed like the one in post #1, experience has shown that the correct .model name (or .subckt name) should be the first thing verified.
Thank you very much for the explanation.
I got always confused with this spice model and never understood a rule of it. and here I am stuck again with smaj5_0a zener diode where I do not know how to run it again due to the same error!! I named it MDD1, MDR, MDD3, MDRBV and smaj5_0a and still same error.
 

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eetech00

Joined Jun 8, 2013
3,154
Thank you very much for the explanation.
I got always confused with this spice model and never understood a rule of it. and here I am stuck again with smaj5_0a zener diode where I do not know how to run it again due to the same error!! I named it MDD1, MDR, MDD3, MDRBV and smaj5_0a and still same error.
The diode is defined as a "subcircuit" using the ".subckt" keyword. Therefore, in LTspice, the symbol prefix attribute needs to be changed to "X" instead of "D"

1644594978602.png
 

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Thread Starter

TarikElec

Joined Oct 17, 2019
80
There are plenty of spice documents on the web that explain spice code and how it is structured.
The "X" in the LTspice symbol is an association with a type of component in spice code.
Yes yes. I am doing it now. do you think there are engineers who are doing this job? I have heard something like analog modelling
 

Papabravo

Joined Feb 24, 2006
18,426
Yes yes. I am doing it now. do you think there are engineers who are doing this job? I have heard something like analog modelling
You can see that many companies are now providing spice models along with datasheets on their websites. Some companies are doing a better job than others.
 
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