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I am unable to add and use the BS138 (BSS138) model for simulation Iin LTSpice. can anyone help me with this

[email protected]
 

i have the following 3 files related to it.

i dont know which one to use

and which standard component to use in place of this component
 

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Please DO NOT send us to third-party sites for data. Upload your .ZIP to Files => Temp, and then tell us you did that. Meanwhile, you mean BSS138, not BS138.? The way to add third-party models is explained in the Help, but it's best to put the model file in the same folder as the .ASC. Don't try to add it to LTspice's native files, which is not straightforward and often leads to problems.

======================================================================================
Best wishes John Woodgate OOO-Own Opinions Only

Rayleigh, Essex UK

I hear, and I forget. I see, and I remember. I do, and I understand. Xunzi (340 - 245 BC)


On 2023-07-06 19:05, vedhaanth648@... wrote:

i have the following 3 files related to it.

i dont know which one to use

and which standard component to use in place of this component
 

Please do not point us to some random website that has your files, even if it is your own.? UPLOAD your files to our group's Files section, into the "Temp" folder:

? ??/g/LTspice/files/Temp

Maybe you forgot to read what it says on the group's main webpage: "do not point us to other ("third party") file storage websites".? Go back now and read the group's main webpage.

Andy
 

vedhaanth648,

I uploaded your file for you.? It is in the Temp folder.? BSS138.zip.

To answer your question "i dont know which one to use", use whichever one you want to use.? All three of them appear to be SPICE models, so any of them should work in SPICE (and LTspice).? Take your pick.??They appear to be MOSFET models.? Two of them can be used directly.? But one of them (BSS138.lib) is a special model that has a fourth pin for temperature.? To use that one, you will need to create (or borrow) a special MOSFET symbol that has the fourth pin, and then use that pin correctly.? That might mean connecting the fourth pin to a voltage source, or to an RC network to represent a heatsink.

So I recommend starting with the other two models first.

The other two models are ordinary 3-terminal subcircuits.? You can use them with LTspice's normal MOSFET symbols (either NMOS or PMOS as appropriate).? After adding the symbol to your schematic, then use Ctrl-right-click on the symbol, and change the Prefix value to "X" (without the quotes), and click OK.

Andy
 

The files are dated, use the most recent one.
 

Richard wrote, "The files are dated, use the most recent one."

That's one way of thinking about it, but probably not the best.? Newer does not mean better.? You might get the one made by someone who just got out of high school and first used SPICE two weeks ago.??You could also base your decision on who made the model, or what company published it (may or may not be the same).? Preferably, you should try the models and compare them with datasheets, or with measurements of real parts.

Andy
 

I just went to diodes.com and found the newest spice model for the

 

Richard wrote, "I just went to diodes.com and found the newest spice model for the?"

And ... what is your point?

That was one of the four BSS138 SPICE models that vedhaanth648 already pointed to, yesterday, when they asked their question.? What do you make of that one particular model, and why should we think it is either better or worse than other BSS138 SPICE models?

I think it's funny that you call this one "the newest spice model" when it is in fact 16 years old.? I found many other BSS138 models which are newer than that one.? So the "newest spice model" you found is definitely not newest!? Check your facts.

But as I said previously, newness does not imply goodness.

Just an FYI -- I have four BSS138 SPICE models from Diodes Inc.? And I've got three more from Onsemi, one from NXP, and six from Infineon.? What makes any model good?? I'd say it is how well it agrees with what the part actually does, which is best determined by purchasing a few dozen samples from various manufacturers, and hooking each one up to some test equipment.

Andy
 

I have made a VMOS model based on the Onsemi datasheet, which adheres pretty well to all the graphs. Unfortunately, I can't upload ATM, as our power has been taken out by a big thunderstorm.

--
Regards,
Tony

On 7 Jul 2023 19:06, Andy I <AI.egrps+io@...> wrote:
Richard wrote, "I just went to diodes.com and found the newest spice model for the?"

And ... what is your point?

That was one of the four BSS138 SPICE models that vedhaanth648 already pointed to, yesterday, when they asked their question.? What do you make of that one particular model, and why should we think it is either better or worse than other BSS138 SPICE models?

I think it's funny that you call this one "the newest spice model" when it is in fact 16 years old.? I found many other BSS138 models which are newer than that one.? So the "newest spice model" you found is definitely not newest!? Check your facts.

But as I said previously, newness does not imply goodness.

Just an FYI -- I have four BSS138 SPICE models from Diodes Inc.? And I've got three more from Onsemi, one from NXP, and six from Infineon.? What makes any model good?? I'd say it is how well it agrees with what the part actually does, which is best determined by purchasing a few dozen samples from various manufacturers, and hooking each one up to some test equipment.

Andy

 

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I have uploaded an LTspice VDMOS model for the Onsemi BSS138.

The uploaded zip includes a model validation report that compares the key testjig simulation results to the Onsemi datasheet graphs.

--
Regards,
Tony

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