Re: Looking for ideal fully differential amplifier spice model
On Sat, Dec 21, 2024 at 11:09 PM, Tom wrote:
Looking for ideal fully differential amplifier spice model for XSPICE simulations.
I am a little confused about the request.? Does that mean you want a model that will be used in XSPICE?? Or one for LTspice that behaves similarly to a model you already have for XSPICE?
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If it is for LTspice, can it be for LTspice only (using LTspice-unique constructs)?
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Andy
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Looking for ideal fully differential amplifier spice model
Looking for ideal fully differential amplifier spice model for XSPICE simulations. The one I have based on the XSPICE "gain" code model doesn't have any CMRR or care if outputs are swapped. Anything based on dependent sources would be good.
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* XSPICE Fully Differential OpAmp
.subckt opamp inp inn outp outn in_offset=0 gain=300e3 out_offset=0
aint %vd(inp inn) %vd(outp outn) amp
.model amp gain (in_offset='in_offset' gain='gain' out_offset='out_offset')
.ends opamp
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The SE output OpAmp using the same structure works fine...
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Re: Whither 4053_tercio.asy
Andy,
I had to do a deeper search in my archive, but found them.
I uploaded a newer zip file with the missing asy files.
Mike
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Re: Whither 4053_tercio.asy
Story of my life! That's why I usually use
'JMW' rather than 'JW', but at one time there were at least
three people called John Michael Woodgate (only very distantly
related, if at all) in Britain.
On 2024-12-21 23:36, Andy I via
groups.io wrote:
On Sat, Dec 21, 2024 at 06:31 PM, John Woodgate wrote:
I can live without them,
...
Sorry!? That was the other John W (Waugaman).
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--
OOO - Own Opinions Only
Best Wishes
John Woodgate
Keep trying
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Re: Whither 4053_tercio.asy
On Sat, Dec 21, 2024 at 06:31 PM, John Woodgate wrote:
I can live without them, ...
Sorry!? That was the other John W (Waugaman).
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Re: Whither 4053_tercio.asy
I can live without them, and I'm sure Andy
will provide all the help you need.
On 2024-12-21 23:25, Andy I via
groups.io wrote:
On Sat, Dec 21, 2024 at 06:17 PM, Mike Fraser wrote:
I found the files in my offline LTspice storage location.
Files are uploaded as 4053_tercio.zip.
Thanks, Mike.
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I don't know if it matters (to John W), but your uploaded
.zip file is missing the symbols "1To2.asy" and "switchana.asy".
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Andy
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--
OOO - Own Opinions Only
Best Wishes
John Woodgate
Keep trying
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Re: Whither 4053_tercio.asy
On Sat, Dec 21, 2024 at 06:17 PM, Mike Fraser wrote:
I found the files in my offline LTspice storage location.
Files are uploaded as 4053_tercio.zip.
Thanks, Mike.
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I don't know if it matters (to John W), but your uploaded .zip file is missing the symbols "1To2.asy" and "switchana.asy".
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Andy
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Re: Whither 4053_tercio.asy
John & Andy,
I found the files in my offline LTspice storage location.
Files are uploaded as 4053_tercio.zip.
I have no idea if the files are current with the latest Bordodynov library.
You will simply need to try the example and see if it works.
Mike?
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Re: Whither 4053_tercio.asy
A much older version of "SwitchAna.Lib" was also mentioned in this 2008 message thread:
but it appears they did not successfully upload the library containing that and other files.
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It looks like they may have uploaded the whole thing to a different Yahoo!Group which does not exist anymore.? There may be some hope of finding it again but don't hold your breath.? (At one time I downloaded the files from the extinct LTspiceDocs group, but I might not be able to find them today.)
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That 2008 message thread also mentions "LTspicePlus", which I think was another large collection of user-contributed models and files to use with LTspice.? I think you can find LTspicePlus at the LTwiki website, here:
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Scroll down to "New Updated Version".
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I think LTspicePlus downloads as a self-extraction .exe file - so it is really a .zip file with self-unzipping code included.? Maybe that librarry contains all the missing information you seek.
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Andy
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Re: Whither 4053_tercio.asy
On Sat, Dec 21, 2024 at 02:40 PM, John Waugaman wrote:
The analog switch library "SwitchAna.Lib" makes reference to various symbols (e.g.? "4053_tercio.asy") and phrases like "The model needs two params: Vcc & Vel see the circuit example..".? Where might I find these?
It's difficult to trace back in time, 7 years later.? But the library file "SwitchAna.Lib" was uploaded and mentioned in this thread:
Unfortunately, that .Lib file was the only thing uploaded then.? Bordodynov was the uploader, and he is still occasionally active in this group so maybe he can fill in the gaps.
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Regarding the missing parameters, just define them yourself, maybe something like this:
? ? .param Vcc=10? ?(use your actual voltage)
? ? .param Vel=1? ?(guessing that Vel is a relative speed setting where 1 = nominal)
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For the LTspice symbol, I suggest drawing it yourself.? So, for the 4053, draw the symbol for a CD4053, see how the pins line up with the .SUBCKT definition (".Subckt 4053_tercia I inh xio yio xoy"), and you might be good to go.
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That .Lib file apparently came from somewhere else, and the one .Lib file might be the only thing that made it into this group's Files.? I suggest carefully reading the thread above about the CD4053 to see if you can find any clues.? Otherwise, wait to hear from Bordodynov himself.
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Andy
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The analog switch library "SwitchAna.Lib" makes reference to various symbols (e.g.? "4053_tercio.asy") and phrases like "The model needs two params: Vcc & Vel see the circuit example..".? Where might I find these?
John
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Re: OPA891 / OPA2891 Model Needed
On Sat, Dec 21, 2024 at 12:20 PM, <info@...> wrote:
I added "OPA891" to Value 2 in both my OPA891 and OPA2891 symbols and now my sims all work using my user defined locations.
Just to be clear -
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Adding "OPA891" as the Value2 attribute has nothing to do with putting your symbols and models in your user-defined locations.
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Andy
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Re: OPA891 / OPA2891 Model Needed
Problem solved:
I added "OPA891" to Value 2 in both my OPA891 and OPA2891 symbols and now my sims all work using my user defined locations.
Thanks to all who helped me figure this out. You spent precious time helping me and I deeply grateful.
Steve
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On 2024-12-21 11:46, Andy I via groups.io wrote:
On Sat, Dec 21, 2024 at 10:56 AM, <info@...> wrote:
It is a pain to copy the model to every directory with an .asc in it and add the .lib directive to every simulation.? I really want to be able to add the symbol to the schematic and have LTspice find the proper model by itself.
....? Keep that model file in the same directory with your schematic - or move it to one of your User-defined Lib. Search Path
I don't know how you missed it.? Put the symbol in a folder in your User-defined Symbol Search Path, and put the model in a folder in your User-defined Library Search Path.? Those User-defined Lib. and Sym. Search Paths are in the LTspce Control Panel.? Symbols and models that are there in those user-defined locations, can be "seen" by LTspice schematics anywhere on your computer.? They are the user's equivalent of LTspice's own libraries.
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User-defined Lib. and Sym. Search Paths have been a part of LTspice for many versions and many years.? I think they were added in LTspice XVII, which dates them to eight years ago in 2016.
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This means that the "Andy" modified model should be able to live in my directory and the symbol should be able to call it, but I am not calling it correctly in the attributes of the symbol.
The model - whether it was "my" model or any other model - is totally, completely, 100% unrelated to where it lives!? If Windows finds the file, then LTspice finds the file and it does not care whose file it was.? If you make your own model file, great.? Go for it.? ?If you leave the model file unmodified from T.I., great.? Go for it.? No matter whether it is modified or the original unmodified file from T.I., it makes no difference to whether Windows and LTspice can find it.? The contents of the file and the location of the file are two completely independent things.
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Does renaming the Model Suffix from .lib to .sub matter?
I thought we made this clear already.? THE FILENAME DOES NOT MATTER, as long as you refer to it by its actual filename.? You can save or rename the model file with the filename FOOBAR.ARRGH if you want to.? As long as you call it by its actual filename, LTspice doesn't care whether the name ends in .lib or .sub or .mod or .txt or .doc or .xyzzy or even no extension.? All you need to do is make sure that you refer to it by its ACTUAL filename.? The filename extension is part of the filename. Don't let Microsoft Windows trick you into thinking that the filename's extension carries some sort of magic.? It doesn't.
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Andy
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Re: LTspice 24.1 Beta Available Now
They can work on the bugs to their hearts content, but it might be reasonable to leave the link there so more people can continue the search.
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Re: OPA891 / OPA2891 Model Needed
On Sat, Dec 21, 2024 at 10:56 AM, <info@...> wrote:
It is a pain to copy the model to every directory with an .asc in it and add the .lib directive to every simulation.? I really want to be able to add the symbol to the schematic and have LTspice find the proper model by itself.
....? Keep that model file in the same directory with your schematic - or move it to one of your User-defined Lib. Search Path
I don't know how you missed it.? Put the symbol in a folder in your User-defined Symbol Search Path, and put the model in a folder in your User-defined Library Search Path.? Those User-defined Lib. and Sym. Search Paths are in the LTspce Control Panel.? Symbols and models that are there in those user-defined locations, can be "seen" by LTspice schematics anywhere on your computer.? They are the user's equivalent of LTspice's own libraries.
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User-defined Lib. and Sym. Search Paths have been a part of LTspice for many versions and many years.? I think they were added in LTspice XVII, which dates them to eight years ago in 2016.
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This means that the "Andy" modified model should be able to live in my directory and the symbol should be able to call it, but I am not calling it correctly in the attributes of the symbol.
The model - whether it was "my" model or any other model - is totally, completely, 100% unrelated to where it lives!? If Windows finds the file, then LTspice finds the file and it does not care whose file it was.? If you make your own model file, great.? Go for it.? ?If you leave the model file unmodified from T.I., great.? Go for it.? No matter whether it is modified or the original unmodified file from T.I., it makes no difference to whether Windows and LTspice can find it.? The contents of the file and the location of the file are two completely independent things.
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Does renaming the Model Suffix from .lib to .sub matter?
I thought we made this clear already.? THE FILENAME DOES NOT MATTER, as long as you refer to it by its actual filename.? You can save or rename the model file with the filename FOOBAR.ARRGH if you want to.? As long as you call it by its actual filename, LTspice doesn't care whether the name ends in .lib or .sub or .mod or .txt or .doc or .xyzzy or even no extension.? All you need to do is make sure that you refer to it by its ACTUAL filename.? The filename extension is part of the filename. Don't let Microsoft Windows trick you into thinking that the filename's extension carries some sort of magic.? It doesn't.
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Andy
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Re: OPA891 / OPA2891 Model Needed
It will nearly do that if you create your own
libraries for symbols and models. See 'Settings > Search
paths' in the Help. You do have to select the folder from a
drop-down list.
? I
really want to be able to add the symbol to the schematic and have
LTspice find the proper model by itself.
--
OOO - Own Opinions Only
Best Wishes
John Woodgate
Keep trying
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Re: OPA891 / OPA2891 Model Needed
Tony and Andy,
Thanks for the demo schematic which proves that the model itself is OK and that changing the line that defines the functions to match opamp2 works perfectly when the model is in the same directory as the .asc file and the .lib command defines the model.
It is a pain to copy the model to every directory with an .asc in it and add the .lib directive to every simulation.? I really want to be able to add the symbol to the schematic and have LTspice find the proper model by itself.
This means that the "Andy" modified model should be able to live in my directory and the symbol should be able to call it, but I am not calling it correctly in the attributes of the symbol.
BTW I did not confuse the netlist numbers on the symbol with IC package pins.? I agree that the symbol is not pointing to the Model due to an error in my attribute editing.
Does renaming the Model Suffix from .lib to .sub matter?
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On 2024-12-21 04:18, Tony Casey wrote:
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
To save you the frustration of more wasted time, I have uploaded an OPA891 demo schematic, including a model suitably modified according to the exact advice given by Andy, previously
--
Regards,
Tony
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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
To save you the frustration of more wasted time, I have uploaded an
OPA891
demo schematic, including a model suitably modified according
to the exact advice given by Andy, previously
--
Regards,
Tony
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Re: OPA891 / OPA2891 Model Needed
On Sat, Dec 21, 2024 at 12:49 AM, <info@...> wrote:
It gives the same error every time:
" Unknown subcircuit called in:
xu1 0 n002 n003 v+ v- tss/opa891_model_v1p1.lib opa891"
There are multiple problems with that line, pointing to a few mistakes.
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The pin-order is all messed up.? It seems to have connected the input pins to net N002 and ground, the power pins to nets N003 and V+, and the output goes to net V-.? That can't be right.? Did you alter the pin-order of the symbol?? Don't do that.? Did you mistakenly use package pin numbers, thinking that the ORDER of pins is the same as the package pin number?? Don't do that either.? SPICE/LTspice does not want to know what the package pin numbers are.
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The name "tss/opa891_model_v1p1.lib" is stuck in there where it does not belong.? That might cause LTspice to try to find a subcircuit by that name.? Of course it does not exist.? Furthermore, I believe that the model file itself was never being loaded at all.? That would surely cause problems because LTspice would be totally unaware of that subcircuit, so it would indeed be "unknown".
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I strongly suggest deleting the SpiceModel attribute, and use the ModelFile attribute instead.? The SpiceModel attribute does not necessarily refer to a filename that you want to be loaded.? It does in the unique case where both the Value and Value2 attributes are defined, but I think not otherwise.? You probably did not use it that way with both Value and Value2.
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People can get themselves in trouble by trying to use LTspice in ways it was not supposed to be used.? And then they waste time trying to fix problems that they made for themselves.
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Andy
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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.
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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.
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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.
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"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.
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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.
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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.
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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.
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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.
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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.
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Andy
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John Woodgate
John Waugaman
Tony Casey