Re: OPA891 / OPA2891 Model Needed
It appears that the symbol is able to call the OPA891 spice model without problem.
I edited the model to make the pins agree with the conventional symbols, but it won't run
I used the TI model unedited and I changed the symbol pin net numbers to match, but it won't run.
It gives the same error every time:
" Unknown subcircuit called in:
xu1 0 n002 n003 v+ v- tss/opa891_model_v1p1.lib opa891"
I believe that someone has this model running, but I don't understand the inner workings of LTspice well enough to troubleshoot this error.
Thanks for all your help.
Steve
?
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On 2024-12-21 00:09, Andy I via groups.io wrote:
On Fri, Dec 20, 2024 at 03:38 PM, <info@...> wrote:
Since Version 24 came it appears that I am supposed to keep my user defined models in a different place than the factory models,
That is not new to Version 24.? I think it has been such ever since LTspice IV.? People who ignored the advice and tried adding their models in the wrong place, sometimes found that it did not work.? It was a risky thing to add your models to the program's own library area (which I assume is what you meant by "the factory models"). Creating user-defined Sym. and Lib. Search Paths has been part of LTspice XVII for some years now.? If you wish having central locations for your model files, that is probably the best way to do it, and has been for some time now.
?
I edited the Pin locations in the TI supplied OPA891_Model_V1p1.lib and renamed the edited version to OPA891_Model_V1p1SAH.lib.? I presume that I must copy that entire file to a directory where the symbol can call it.
Yes, that entire file is the SPICE model for the OPA891.? If you did not have the model file where LTspice can find it, then LTspice would not find it and the simulation would be in trouble.? That is true.
?
SpiceModel? ?TSS/OPA891.sub? (my customized models are in a TSS subdirectory)
I might be mistaken, but I believe the ModelFile attribute is the better one to have used.? There are certain "exceptions" that one gets into when using the SpiceModel attribute so I would avoid that one if I were you.
?
"TSS/OPA891.sub" would be correct only if that is the filespec of your model file.? But you said that the model file's filename is "OPA891_Model_V1p1SAH.lib" so that is a problem.? It makes no sense to call a file using a different filename than it actually has.? AI aside, computers don't like guessing what you were thinking.
?
It seems that the SpiceModel attribute should be?OPA891_Model_V1p1SAH.lib? rather than .sub? ...
Of course!? See above.? The filename you used must match the actual filename.? Because you are telling it the filename of the file to load, that filename must be the actual filename.
?
There is a whole lot of other stuff in that file other than the opamp model itself.? ...
No, there is no other stuff.? Everything in that file is part of the model.
?
It is not unusual for a model to use more than one subcircuit, all of which are part of the model.? If you eliminated the rest, it wouldn't work.
?
The structure T.I. used here is not one that I like, where they put all the secondary subcircuits separate from the main one, instead of inside it.? I would have done it differently..? There is a small possibility of having conflicts between those secondary subcircuits and another model in the same simulation.? The likelihood of that is very small, but could happen if you use another T.I. model in the same simulation.? Oh well.
?
Should the symbol call the whole .lib file and it will figure out which part to use?
It will use all of it.? It will do the right thing.? That is how SPICE works.
?
Andy
?
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Re: OPA891 / OPA2891 Model Needed
On Fri, Dec 20, 2024 at 03:38 PM, <info@...> wrote:
Since Version 24 came it appears that I am supposed to keep my user defined models in a different place than the factory models,
That is not new to Version 24.? I think it has been such ever since LTspice IV.? People who ignored the advice and tried adding their models in the wrong place, sometimes found that it did not work.? It was a risky thing to add your models to the program's own library area (which I assume is what you meant by "the factory models"). Creating user-defined Sym. and Lib. Search Paths has been part of LTspice XVII for some years now.? If you wish having central locations for your model files, that is probably the best way to do it, and has been for some time now.
?
I edited the Pin locations in the TI supplied OPA891_Model_V1p1.lib and renamed the edited version to OPA891_Model_V1p1SAH.lib.? I presume that I must copy that entire file to a directory where the symbol can call it.
Yes, that entire file is the SPICE model for the OPA891.? If you did not have the model file where LTspice can find it, then LTspice would not find it and the simulation would be in trouble.? That is true.
?
SpiceModel? ?TSS/OPA891.sub? (my customized models are in a TSS subdirectory)
I might be mistaken, but I believe the ModelFile attribute is the better one to have used.? There are certain "exceptions" that one gets into when using the SpiceModel attribute so I would avoid that one if I were you.
?
"TSS/OPA891.sub" would be correct only if that is the filespec of your model file.? But you said that the model file's filename is "OPA891_Model_V1p1SAH.lib" so that is a problem.? It makes no sense to call a file using a different filename than it actually has.? AI aside, computers don't like guessing what you were thinking.
?
It seems that the SpiceModel attribute should be?OPA891_Model_V1p1SAH.lib? rather than .sub? ...
Of course!? See above.? The filename you used must match the actual filename.? Because you are telling it the filename of the file to load, that filename must be the actual filename.
?
There is a whole lot of other stuff in that file other than the opamp model itself.? ...
No, there is no other stuff.? Everything in that file is part of the model.
?
It is not unusual for a model to use more than one subcircuit, all of which are part of the model.? If you eliminated the rest, it wouldn't work.
?
The structure T.I. used here is not one that I like, where they put all the secondary subcircuits separate from the main one, instead of inside it.? I would have done it differently..? There is a small possibility of having conflicts between those secondary subcircuits and another model in the same simulation.? The likelihood of that is very small, but could happen if you use another T.I. model in the same simulation.? Oh well.
?
Should the symbol call the whole .lib file and it will figure out which part to use?
It will use all of it.? It will do the right thing.? That is how SPICE works.
?
Andy
?
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Re: OPA891 / OPA2891 Model Needed
Since Version 24 came it appears that I am supposed to keep my
user defined models in a different place than the factory
models, However I have not yet made the switch from the file
structure I had previously.? I keep my models in subdirectories
in the factory lib and sym folders.
That has been the advice from here for many years prior to V24.
I edited the Pin locations in the TI supplied
OPA891_Model_V1p1.lib and renamed the edited version to OPA891_Model_V1p1SAH.lib.?
I presume that I must copy that entire file to a directory
where the symbol can call it.
I have made 2 symbols: OPA891 and OPA2891 which should both
call the same Model.
I edited the Attributes as follows:
Prefix X
SpiceModel? ?TSS/OPA891.sub? (my customized models are in a TSS
subdirectory)
Value? ? ?OPA891?
Remaining attributes are blank
It seems that the SpiceModel attribute should be?OPA891_Model_V1p1SAH.lib?
rather than .sub. along with directions for the symbol to find
it.
The SpiceModel attribute is optional. But if you assign a value to
it, that should be exactly the name the of the model file. Whether
this has a "sub", "lib", or any other suffix makes no difference. If
you leave it blank, you need to inform LTspice of the name of the
model file some other way. I prefer adding:
.lib ModelFileName
..as a SPICE directive. This is visible on the schematic and
unambiguous. It is also easy to view this file file by
Right-clicking on the directive > Open.
There is a whole lot of other stuff in that file other
than the opamp model itself.? Should the symbol call the whole
.lib file and it will figure out which part to use?
That is exactly what the .lib directive does.
Sorry for the newbee questions, but figuring out the
directory structure in version 24 isn't easy for me.
I'm still smarting from when an attempted install of
version 24 erased my entire Win 7 LTSpice installation without
warning
That's strange, as I'm not sure V24 will run on Win7, according to
the ADI website.
You would be wise to back up critical files before making any major
changes to your system. I would imagine you have heard that advice
before. I recommend you have a regular backup regime in place,
preferably an automatic schedule. You never know when disaster will
strike - don't make it any worse by not having backups.
--
Regards,
Tony
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Re: OPA891 / OPA2891 Model Needed
It's unwise to store your stuff in the LTspice
'working copies' of the native folders, that also? should never
be touched. This is because your 'LTspice' becomes different
from those of everyone else, and that complicates sharing and
advising. There are two safe places to store, and I recommend
using both - the folder that holds your .ASC file and your
personal library, set up in User-defined Lib. Search
Path folders.
Since Version 24 came it appears that I am supposed to keep my
user defined models in a different place than the factory
models, However I have not yet made the switch from the file
structure I had previously.? I keep my models in subdirectories
in the factory lib and sym folders.
I edited the Pin locations in the TI supplied
OPA891_Model_V1p1.lib and renamed the edited version to OPA891_Model_V1p1SAH.lib.?
I presume that I must copy that entire file to a directory
where the symbol can call it.
I have made 2 symbols: OPA891 and OPA2891 which should both
call the same Model.
I edited the Attributes as follows:
Prefix X
SpiceModel? ?TSS/OPA891.sub? (my customized models are in a TSS
subdirectory)
Value? ? ?OPA891?
Remaining attributes are blank
It seems that the SpiceModel attribute should be?OPA891_Model_V1p1SAH.lib?
rather than .sub. along with directions for the symbol to find
it.
There is a whole lot of other stuff in that file other
than the opamp model itself.? Should the symbol call the whole
.lib file and it will figure out which part to use?
Sorry for the newbee questions, but figuring out the
directory structure in version 24 isn't easy for me.
I'm still smarting from when an attempted install of
version 24 erased my entire Win 7 LTSpice installation without
warning.
?
Many thanks,
Steve
On 2024-12-20 09:45, Andy I via groups.io wrote:
Just in case it was not obvious already -
?
Use LTspice's "opamp2" symbol with this model, after making
the change to the model file.
?
Change the name next to the symbol from "opamp2" to
"OPA891".
?
Also add this line:
? ? .lib OPA891_Movel_V1p1.lib
to your schematic.? Keep that model file in the same
directory with your schematic - or move it to one of your
User-defined Lib. Search Path folders.
?
Andy
?
--
OOO - Own Opinions Only
Best Wishes
John Woodgate
Keep trying
|
Re: OPA891 / OPA2891 Model Needed
Since Version 24 came it appears that I am supposed to keep my user defined models in a different place than the factory models, However I have not yet made the switch from the file structure I had previously.? I keep my models in subdirectories in the factory lib and sym folders.
I edited the Pin locations in the TI supplied OPA891_Model_V1p1.lib and renamed the edited version to OPA891_Model_V1p1SAH.lib.? I presume that I must copy that entire file to a directory where the symbol can call it.
I have made 2 symbols: OPA891 and OPA2891 which should both call the same Model.
I edited the Attributes as follows:
Prefix X
SpiceModel? ?TSS/OPA891.sub? (my customized models are in a TSS subdirectory)
Value? ? ?OPA891?
Remaining attributes are blank
It seems that the SpiceModel attribute should be?OPA891_Model_V1p1SAH.lib? rather than .sub. along with directions for the symbol to find it.
There is a whole lot of other stuff in that file other than the opamp model itself.? Should the symbol call the whole .lib file and it will figure out which part to use?
Sorry for the newbee questions, but figuring out the directory structure in version 24 isn't easy for me.
I'm still smarting from when an attempted install of version 24 erased my entire Win 7 LTSpice installation without warning.
?
Many thanks,
Steve
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Show quoted text
On 2024-12-20 09:45, Andy I via groups.io wrote:
Just in case it was not obvious already -
?
Use LTspice's "opamp2" symbol with this model, after making the change to the model file.
?
Change the name next to the symbol from "opamp2" to "OPA891".
?
Also add this line:
? ? .lib OPA891_Movel_V1p1.lib
to your schematic.? Keep that model file in the same directory with your schematic - or move it to one of your User-defined Lib. Search Path folders.
?
Andy
?
|
Re: OPA891 / OPA2891 Model Needed
Very good advice. You can also, with
advantage, do both; save in both locations, so that in 2027 you
won't need to recall which? schematic directory the model is in.
On 2024-12-20 14:45, Andy I via
groups.io wrote:
Keep that model
file in the same directory with your schematic - or move it to one
of your User-defined Lib. Search Path folders.
--
OOO - Own Opinions Only
Best Wishes
John Woodgate
Keep trying
|
Re: OPA891 / OPA2891 Model Needed
Just in case it was not obvious already -
?
Use LTspice's "opamp2" symbol with this model, after making the change to the model file.
?
Change the name next to the symbol from "opamp2" to "OPA891".
?
Also add this line:
? ? .lib OPA891_Movel_V1p1.lib
to your schematic.? Keep that model file in the same directory with your schematic - or move it to one of your User-defined Lib. Search Path folders.
?
Andy
?
|
Re: OPA891 / OPA2891 Model Needed
Let us know if you encounter any problems with that model.? I did not try it yet.
?
Andy
?
?
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Re: OPA891 / OPA2891 Model Needed
On Fri, Dec 20, 2024 at 09:18 AM, <info@...> wrote:
TI is publishing the OPA891 model only for their TINA program.
It is a SPICE model.
?
TINA-TI can use either generic SPICE models, or models using their own format which only work in their program.? Fortunately, this one is a SPICE model.? ?In that respect, there should be nothing to convert.
?
I also understand that the TINA model uses non-standard pin order to assign nodes to its opamp symbol so that needs to be fixed.
That is true - to the extent that the pin-order is really a "standard".? There is a customary pin-order that most op-amp SPICE models use, but not all.? This is one of the exceptions.
?
There are multiple ways to "fix" that.? The easiest, is to open the OPA891 SPICE? model in a text editor (LTspice has a pretty good text editor built-in), and change this line:
? ? .subckt OPA891 IN+ IN- OUT V+ V-
to this:
? ? .subckt OPA891 IN+ IN- V+ V- OUT
While you are at it, also delete the very last line in the file:
? ? .END
because it has no place being in a SPICE model.? Then save the file.
?
Andy
?
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OPA891 / OPA2891 Model Needed
TI is publishing the OPA891 model only for their TINA program. I understand there is a procedure to extract the TINA model information and make a LTSpice-compatible model.
I also understand that the TINA model uses non-standard pin order to assign nodes to its opamp symbol so that needs to be fixed.
I struggle to install a new spice model into my installation, mainly because I do it very seldom and forget how to do it when I need to do it again.? Has someone already come up with a working LTSpice model of the 0PA891 that I can install in my system?
Thanks!
|
I suppose that Rds depends on die temperature,
too, so large signal Rds is a thicket, not a value.
On 2024-12-20 12:25, Andy I via
groups.io wrote:
But RON is defined for linear region right??
Even in the FET's linear region, it is nonlinear.? It is
unlikely that a JFET or MOSFET has an Rds that is actually
linear, in the so-called linear region.? It "bends", even
there.
?
But if you found a FET whose Rds was strictly linear, then
there would be no difference between small-signal and
large-signal Rds.
?
Andy
?
--
OOO - Own Opinions Only
Best Wishes
John Woodgate
Keep trying
|
On Thu, Dec 19, 2024 at 09:41 PM, <abanindra.kumarmandal.ece24@...> wrote:
But RON is defined for linear region right??
Even in the FET's linear region, it is nonlinear.? It is unlikely that a JFET or MOSFET has an Rds that is actually linear, in the so-called linear region.? It "bends", even there.
?
But if you found a FET whose Rds was strictly linear, then there would be no difference between small-signal and large-signal Rds.
?
Andy
?
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On Thu, Dec 19, 2024 at 10:03 PM, <abanindra.kumarmandal.ece24@...> wrote:
What will be the expression for RON then??
Either one.? They would be the same.? (But unlikely.)
?
Andy
?
?
?
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What will be the expression for RON then??
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On Thu, Dec 19, 2024 at 09:41 PM, <abanindra.kumarmandal.ece24@...> wrote:
But RON is defined for linear region right??
Not necessarily.
?
If it is linear, then you know that the small-signal and large-signal definitions would be the same, so there would be no question.
?
Andy
?
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But RON is defined for linear region right??
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Re: Separate from .CKT for .lib file
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
?
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Re: Separate from .CKT for .lib file
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.
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Separate from .CKT for .lib file
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.
?
|
Re: Placing a Symbol and its .cir "Manually" into a schematic
I finally saved a copy of the symbol in the local (¡°.¡±) folder, one of the two I now have access to.
?
?
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From: [email protected] < [email protected]> On Behalf Of
Tony Casey
Sent: Thursday, December 19, 2024 2:29 PM
To: [email protected]
Subject: EXTERNAL: Re: [LTspice] Placing a Symbol and its .cir "Manually" into a schematic
?
On 19/12/2024 22:29, Bell, Dave via groups.io wrote:
You should be able to bring up the current folder from F2 by selecting it from the "Top Directory" drop-down selector at the top of the dialogue.
--
Regards,
Tony
|
Tony Casey
John Woodgate
Bell, Dave