You can either create a symbol, or use a part (like an op amp) and link a circuit file to it. The thing to keep in mind with lt spice is the .asc files link .asy parts in the graphical editor together. The pins on these have to match the circuit library files or you might unintentionally swap a pin. After that a netlist is generated (which you can check to make sure the pins are in the right order) under view spice netlist.
It is possible in LTspice IV to create a new symbol from scratch for a
third-party model but who has the time? Follow these easy steps to
generate a new symbol for a third-party model defined in a subcircuit
- Open the netlist file that contains the subcircuit definitions in
LTspice (File > Open or drag file into LTspice)
- Right-click the line containing the name of the subcircuit, and
select Create Symbol:
- Create Symbol:
Edit the symbol if needed and save.
To use the new symbol (and associated third party model) in a
schematic, select the symbol from the AutoGenerated directory in the
component library (F2) and place it in your schematic:
If your using a part like (opamp2 or nmosx ect) then do this:
On the link you posted, scroll down to the PSpice model, unzip the folder, and open LM339_5.1 with notepad. Save the file in C:/program
files/LTC/LTspiceIV/lib/sub as LM339.sub. Change "save as type" to
If LTspice is already open, close and then reopen it.
- Open a new schematic window (Leftmost icon on toolbar).
4.Click on the component icon (the AND gate on the toolbar).
- Double-click on [Opamps].
- Scroll all the way to the end and select opamp2.
- Click OK.
- Left-click to place opamp2 symbol on schematic.
- Right-click on symbol to open Component Attribute Editor.
- Left-click on Value.
- In the edit window that says Value = opamp2, change opamp2 to LM339. In general, the value you enter here must be identical to the
subcircuit name in the subcircuit file. In this case, that line reads
.SUBCKT LM339 1 2 3 4 5
- Left-click on the .op icon (rightmost on the toolbar). This is the spice directive icon .
- Type .lib LM339.sub in the window. Left-click on OK.
- Place this spice directive on the schematic by dragging it to where you want to place it, and then left-clicking.
- You are now ready to place and connect other components before simulating.
Source: RonH https://forum.allaboutcircuits.com/threads/importing-models-into-ltspice.36456/