Simetrix Model
Darth Gupta
SIMetrix is able to import simulation models from many sources. In particular, most device manufacturers provide SPICE Models for their components and the vast majority of these are compatible with SIMetrix.This article describes the procedure required to install models and also some of the problems that are commonly experienced with models.
Simulation models consist of a number of lines of text providing a definition of the electrical characteristics of the device. The lines will reside in a file which may also contain other models. Often however, the file will contain just one device model. Typically the files have the extension .CIR, .MOD, .SPI or .LIB, but this is by no means always the case. Note that SIMetrix doesn't care what the file extension is.
Model files will always have either lines beginning .SUBCKT or lines beginning .MODEL and quite commonly you will see both. If there are no lines that start with either of these two words, then the file is not a SPICE model file and will not be useable by SIMetrix.
Unfortunately, its difficult to give detailed instructions on exactly what you do with this link as this varies between sites - and sometimes between different pages on the same site. But the following are, we hope, useful guidelines.
On most sites, you should not click on the link directly, but instead "Save Target As..." (right click pop up menu in Internet Explorer) and select a suitable location to save to on your hard disk. A default file name will usually appear and if this has the extension .MOD, .CIR, .SPI or .LIB, then you can be reasonably confident that you are saving a correctly formatted model. (These aren't the only file extensions used - they are just the most common. )
If the file has the extension .HTML or .HTM then you shouldn't save it, but cancel and then click on the link in the normal way. You will then be directed to a new web page which may have more links on it. In the case of Analog Devices, for example, you will be presented with a legal agreement that you have to agree to first. When you press the "I agree" button, the browser is then directed to display the text of the model. In this case you should now save the page that is displayed. But, and this is important, you must save the page as plain text. The default with Internet Explorer is to save as an HTML file and this will not work as a model. To save as plain text in IE, select "Text file (*.txt)" in the "Save as type" drop down box. You will get a file with the extension .TXT, but that's OK, SIMetrix will handle it. (But you may prefer to change it to some more suitable extension.)
The end result that you want is a text file that contains lines starting with things like ".SUBCKT", ".MODEL" and ".ENDS". It should definitely NOT contain lines containing , , . The latter are HTML tags and if your file has these in it then it means that it has been saved as web page. You should instead save it as text file - see above.
With SIMetrix, all you need to do to install a model is pick up the model file or model files or directory containing model files and drop them in the SIMetrix command shell. That is all you need to do to install the electrical model itself. It may not be all you need to do to use the model in the schematic editor, but we will cover that issue later.
Now select a suitable symbol from Define Symbol for ???. If there is no suitable symbol available, press Auto Create Symbol to create a new one. The new symbol will be functionally correct although it may not be ideal. You can change the pin names if these are not suitable by pressing Edit Pin Names... and you can edit the symbol graphics after the symbol is placed on the schematic.
If you already have a model file, you can use that file for these procedures. Otherwise, a sample file with three SPICE MOSFET models is available for download in Step 1. The three models in this sample file provide three different methods you can use to create the associations:
For this type of model, no additional steps are required because SIMetrix is able to automatically categorize and associate the model with a symbol. This model example is now associated with an nmos_sub symbol and is categorized as NMOS in the SIMetrix/SIMPLIS library.
At times, models are accidentally associated with the wrong symbols. Although no built-in support is available for removing associations within SIMetrix, you can do this manually with a text editor. The user-defined model-to-symbol associations are stored in a text file in the Application Data directory.
I am currently trying to simulate a phase-shifted full bridge converter using UCC28950 in SIMetrix/SIMPLIS but the PSpice model does not work in SIMetrix/SIMPLIS. I suspect that this is the case because the .lib file is encrypted. I wonder if TI provides an unencrypted model so that it can directly be imported to SIMetrix/SIMPLIS library. If not, can anybody help me simulate the UCC28950 in SIMetrix/SIMPLIS in other ways?
Yes, you are correct. The model is encrypted so you will need the unencrypted model to import into other simulators. Please refer to this FAQ for more details. However, although this is not generally the norm at TI, you are in luck since someone has already developed the SIMPLIS model for UCC28950. Please see below.
A model provides an electrical description of the device but not what schematic symbol to use nor what category it should be in the model library browser. SIMetrix is able to determine this for itself if the device is implemented using a .MODEL statement as all .MODELs refer to a particular type of device (NPN, NMOS, Diode etc.). Devices implemented as subcircuits however remain a problem as there is nothing in a .SUBCKT definition which tells SIMetrix what the device is. For example a three terminal regulator and a power MOSFET use identical syntax - SIMetrix can't tell the difference from the syntax alone. To resolve this SIMetrix is shipped with a database of known part numbers providing a named schematic symbol, part category and if relevant a pin mapping order. If the part is in the database, no further action is required by the user and the part will appear in the browser under the correct category and select the correct symbol.
If the model is not in the database and has 2 or 3 terminals, then SIMetrix will attempt to determine the type of device by performing some tests on the model using simulation. If this process is successful, SIMetrix will choose an appropriate schematic symbol without further action required.
If SIMetrix cannot determine what the device is then, in order to use the device on a schematic, you will need to provide the association information. You will be prompted for this information when you place a part on the schematic for the first time and this is often the most convenient method. However, there is also a method of providing the association information in bulk which is advantageous in many cases.
- Install the model itself so that the program knows where to look for it. This is simply a matter of dropping files or folders on the command shell. See Installing Electrical Model.
- Associate the model(s) with a schematic symbol. This process is often automatic and you don't need to do anything - see explanation in the Overview. If this is necessary, you will be prompted for the information required. See Placing New Model on Schematic.
is displayed when you drop a file, it means that no valid SPICE models were found in the file. It does not mean the file has the wrong extension. SIMetrix will accept any extension for model files with the exception of the extensions used for schematic or graph files (sch, sxsch and sxgph).
A while back there was a thread regarding a TI tinaspice model of the LM5117 that would fail convergence on SIMetrix/Simplis (diode discontinuity error). Has that model been tweaked or has another become available?
I doubt a TINA model runs on SIMPLIS. However, I may be able to provide a simplified SIMPLIS model - what functionality is required? For example, control loop / bode plot / compensation frequency domain analysis or load transient time domain analysis?
The TINA model will do a startup in transient simulation but will not do anything requiring a periodic operating point. I need to do a compensation bode plot, line/load transient, and efficiency analysis.
I recommend using the LM5117 Excel quickstart calculator to check the bode plot. Also, WEBENCH is a useful tool for predicting efficiency (our more advanced quickstart calculators, such as that for the LM5145, can also provide efficiency predictions).
Thanks for joining E2E and checking with our team. Unfortunately we do not officially support simulating the TPSI3052-Q1 with SIMetrix or TINA and recommend simulating using PSpice For TI. We do have this E2E thread from 6 months ago where the TPSI3050-Q1 was working in SIMetrix.
Good news! The TPSI3050-Q1 model on SIMetrix has been updated and is working. Please see attached. I tried simulating with the component values you mentioned in the previous E2E thread (albeit for TPSI3052-Q1) and it looks like it is working. Please let me know if there are further questions.
I am aware this is for TPSI3050-Q1. We do not have a SIMetrix model for TPSI3052-Q1. What is your application and what are you intending to understand with the simulation? Maybe there is a workaround here.
I opened this file as such in Simetrix, but I am getting some errors like subcircuit not defined in the model. Later I moved those missing subcircuit definitions from the TPSI-3050 model which you provided earlier to TPSI-3052 model. Even doing so, I am getting this following error.
I understand the issue now. Basically, all Infineon MOSFET Simulation models are validated in SIMetrix. Most of the models work well with LTSpice as well, but few result in errors. The team is already working on these models to make it LTSpice compatible.
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