Can Ltspice Use Pspice Models

LTspice Tutorial: Function 4

This LTspice Tutorial explains how to import third party models into LTspice ^® .

LTspice is non limited to simulating Linear Engineering science parts. 3rd party models can be imported into LTspice likewise. There are 2 types of model that can be imported into LTspice:

.MODEL parts - these are uncomplicated components such as transistors and diodes

.SUBCKT parts - these are more than complex parts made upward of simpler Spice parts (diodes, transistors, resistors etc)

Information technology is important to notation that LTspice looks at the starting time line of the SPICE model to make up one's mind how the model should exist handled. If the part is defined with a .MODEL statement, importing the model is handled one way; if the role is defined with a .SUBCKT statement, importing the model is handled in a slightly different way. Thus we could import ii identical diodes, one defined with a .MODEL statement and 1 defined with a .SUBCKT statement and they are actually handled differently. LTspice looks at the model definition, Not the component to make up one's mind how to import the role.

.MODEL parts:

To import a simple third party SPICE model into LTspice using the .MODEL directive , follow these steps:

Add together a generic component to the schematic that represents the symbol of the SPICE model
Download the SPICE model into the same directory every bit the circuit you are simulating.
Make a note of the filename of the SPICE model, including the file extension.
Add a .include SPICE directive to the schematic that will use the model
Open up the SPICE model and notation the proper noun of the model - this is the text immediately after the .MODEL directive and before the role designator (in the case below this is the text DI_SBG1030L). The SPICE model can exist viewed from within LTspice.
Press <CTRL> then right click over the generic component and change the 'Value' field to the SPICE model name
Ensure the .include SPICE directive contains the exact filename of the SPICE model
Ensure the proper name of the generic component exactly matches the SPICE model proper noun

Here is an case of how to import a Schottky diode into a circuit. FIG one shows a uncomplicated excursion to measure the forward voltage drop across a diode. This can be downloaded here: Diode Exam Circuit

FIG 1

Running the simulation shows the diode has a forrad voltage drib of 653.2mV

Remove diode D1 and supervene upon it with the standard Schottky diode from the LTspice library.

Download the SPICE model of the BAT 54 Schottky diode: BAT 54 SPICE model and salve it in the aforementioned directory as the circuit in FIG 1.

Add the following SPICE directive to your schematic using the symbol:

.include DI_BAT54.txt

To avoid spelling mistakes, use Windows Explorer to highlight and copy the filename including the filename extension (.txt). Paste the text after the include statement.

Open up the SPICE model file (using, say, Notepad) and note the name of the model (in this case it is DI_BAT54). Once again, to avoid spelling mistakes, it is easier to highlight the model name and copy it.

Press <CTRL> Right click over the Schottky diode symbol and paste the text DI_BAT54 into the Value field as shown in FIG 2. Do not put whatever comments in the Spice Model field.

FIG two

The final circuit should look like FIG 3

FIG three

Run the simulation. The forrad voltage drop should now exist 290mV.

If you lot run across errors, check the following:

Has the SPICE file been loaded into the aforementioned directory every bit the simulation file?

Is the part name the same as that specified in the SPICE model?

Does the filename in the .include statement exactly lucifer the SPICE model filename?

It is also worth opening the SPICE model file from inside LTspice and checking its contents. Some text editors can add formatting characters that confuse LTspice.

.SUBCKT parts

A like process can be used to import more than circuitous models. Follow the steps above, except when modifying the Component Attribute Editor (run across FIG 2), ensure the Prefix attribute is marked as X (and not D every bit in FIG 2).

We are now going to compare the operation of the LT6231, (215MHz depression racket op amp) with the LM324 (depression cost op amp).

Download the circuit in FIG 4: Op Amp Examination Excursion

FIG 4

Running this circuit shows the output falls from 1V at dc to 0.707V at about 2.77MHz.

Now remove the LT6231 and supervene upon it with a standard 5 terminal op amp. This is the 'opamp2' model in the Op Amps binder in LTspice.

Download the LM324 model: LM324 model and save information technology in the same directory equally the circuit in FIG 4.

Brand a notation of the SPICE model filename (in this case it is LM324.txt). Add a .include SPICE directive in your schematic as follows:

.include LM324.txt

Open the SPICE model and make a annotation of the SPICE model proper noun (immediately after the .SUBCKT command). In this case it is LM324.

Press <CTRL> Right click over the op amp symbol in the schematic and insert the model name into the Value field equally shown in FIG 5

FIG five

Ensure that the Prefix attribute is filled in with Ten.

Annotation: The SPICE model of some simple components (e.thou. Zener diodes) are divers as a SUBCKT. In this case, the Prefix aspect has to exist 'X' and not 'D' to represent with the .SUBCKT SPICE definition (and non a .MODEL definition).

Creating a Quick Part Outline for 3rd Political party SPICE models

Once the SPICE model has been imported, an outline tin be created for the part. Open the SPICE model in LTspice, move the mouse over the .SUBCKT line, right click and select 'Create Symbol'. A square symbol will appear showing the nodes of the SPICE model.