Electrical – Add LTspice IV library to LTspice XVII

This is defined as a subcircuit:

.SUBCKT PSMN2R0_30PL DRAIN GATE SOURCE

LTSpice needs this to have somewhat special treatment, so you will need to do the following:

CTRL+Right click on the device and you will get this window:

Now edit the Prefix and Value lines: The prefix for a subckt is 'X'. The model name is precisely as defined in the lib file.

Now click OK. You will need to add a spice directive on your schematic:

.include PSMN2R0_30PL.lib This assumes it is in the same directory as the simulation circuit.

LTSpice should now be happy with the part.

Here is what you should see on the schematic:

You can, of course, add it to the LTSpice model tree, but I find it easier to use this method.

First, make yourself a user directory under 'sym':

Before adding anything (I already did, but we will get to that).

Start LTSpice, start a new schematic and then select add component:

I get this view with my parts directory shown:

Close LTSpice for now.

For an opamp (which is what I did here), copy the OPAMP2.sym file from the sym\Opamps directory to your directory and rename it with the name you want (which is what I did in the first picture).

Now get the subcircuit file and save it in the lib\sub directory:

Now open the asy file in your user directory in a text editor:

Here is part of the file:

SYMATTR Value ADA4666
SYMATTR Prefix X
SYMATTR Description Micropower Rail to Rail amplifier
SYMATTR SpiceModel ADA4666.cir

If there are no SYMATTR lines, then add them:

Version 4
SymbolType CELL
LINE Normal -32 32 32 64
LINE Normal -32 96 32 64
LINE Normal -32 32 -32 96
LINE Normal -28 48 -20 48
LINE Normal -28 80 -20 80
LINE Normal -24 84 -24 76
LINE Normal 0 32 0 48
LINE Normal 0 96 0 80
LINE Normal 4 44 12 44
LINE Normal 8 40 8 48
LINE Normal 4 84 12 84
WINDOW 0 16 32 Left 2
WINDOW 3 16 96 Left 2
SYMATTR Value ADA4666
SYMATTR Prefix X
SYMATTR Description Micropower Rail to Rail amplifier
SYMATTR SpiceModel ADA4666.cir
PIN -32 80 NONE 0
PINATTR PinName In+
PINATTR SpiceOrder 1
PIN -32 48 NONE 0
PINATTR PinName In-
PINATTR SpiceOrder 2
PIN 0 32 NONE 0
PINATTR PinName V+
PINATTR SpiceOrder 3
PIN 0 96 NONE 0
PINATTR PinName V-
PINATTR SpiceOrder 4
PIN 32 64 NONE 0
PINATTR PinName OUT
PINATTR SpiceOrder 5

Add any SYMATTR lines immediately before the PIN and PINATTR statements.

I changed the SYMATTR values to give a correct display name (Value), the Description field for what LTSpice shows in the selector window and the SpiceModel to the model I added in the sub folder.

Here it is:

I then place it:

Right click on the part and you get this:

This can now be used in any schematic.

I went through this when I added the Wurth magnetics library a while back.

The keys are:

1. Put the subcircuit in the sub folder

2. Put the symbol file in a directory of your choosing

3. Make sure the SYMMATR statements point at the subcircuit properly, and edit the name and description to get an accurate representation of what it is.

Note that the subcircuit must be complete in its own right.

In your case, you are trying to create a hierarchical block; there is an excellent description at the link.

As links die, here is the procedure:

Make the schematic you desire to use as a hierarchical block and save it with a name

Now label all nets that must have external visibility and save again.

Create a new symbol. The pins on this symbol must have the same name as the labels you attached.

Save this symbol as (the names must be the same for the schematic and symbol).

If your schematic has external models or subcircuits, use the .include directive using full path names in the schematic before saving (so they do not have to be in a working directory).

You should now be able to instantiate your hierarchical block.