Electronic – How to make LTSpice sub-circuits available globally

ltspicesimulationsubcircuit

LTSpice Hierachy block can not be found if it is not in current working directory.

I am using this tutorial to create sub-circuits in LTSpice:

http://www.audio-perfection.com/spice-ltspice/hierarchical-blocks-in-ltspice.html

Everything is fine except that the sub-circuit that I make can not be used globally. Every time that I have a new design I must copy my sub-circuits to the directory that my top-level design resides.

I even moved my sub-circuit (both .asc and .asy files) into a folder under E:\Program Files (x86)\LTC\LTspiceIV\lib\sym but LTSpice can not find it. I suspect there must be a directive such that includes a folder into the global search path (or top-level search path) but I can't locate the option.

I appreciate if you tell me how to make LTSpice sub-circuits available globally?

Update:

This is my inverter_035_1.asc:

Version 4
SHEET 1 880 680
WIRE 208 -96 208 -160
WIRE 272 -96 208 -96
WIRE 208 -80 208 -96
WIRE 160 -32 80 -32
WIRE 272 -32 272 -96
WIRE 272 -32 208 -32
WIRE 80 32 80 -32
WIRE 80 32 -16 32
WIRE 208 32 208 16
WIRE 448 32 208 32
WIRE 208 48 208 32
WIRE 80 96 80 32
WIRE 160 96 80 96
WIRE 400 96 208 96
WIRE 208 176 208 144
WIRE 400 176 400 96
WIRE 400 176 208 176
WIRE 208 240 208 176
FLAG 448 32 out
IOPIN 448 32 Out
FLAG 208 -160 VDD
IOPIN 208 -160 BiDir
FLAG 208 240 GND
IOPIN 208 240 BiDir
FLAG -16 32 in
IOPIN -16 32 In
SYMBOL nmos_035 160 48 R0
SYMATTR InstName M1
SYMATTR Prefix X
SYMATTR Value2 W=1u L=0.35u
SYMATTR SpiceLine ""
SYMBOL pmos_035 160 -80 R0
SYMATTR InstName M2
SYMATTR Value2 W=3u L=0.35u
SYMATTR Prefix X
SYMATTR SpiceLine ""

And this is my inverter_035_1.asy:

Version 4
SymbolType BLOCK
LINE Normal -16 32 -16 -32
LINE Normal 33 0 -16 32
LINE Normal -16 -32 33 0
LINE Normal 64 0 44 0
LINE Normal 0 -48 0 -21
LINE Normal 0 48 0 22
LINE Normal -16 0 -48 0
CIRCLE Normal 44 5 33 -5
PIN -48 0 NONE 8
PINATTR PinName in
PINATTR SpiceOrder 1
PIN 64 0 NONE 8
PINATTR PinName out
PINATTR SpiceOrder 2
PIN 0 -48 NONE 8
PINATTR PinName VDD
PINATTR SpiceOrder 3
PIN 0 48 NONE 8
PINATTR PinName GND
PINATTR SpiceOrder 4

Both files reside in a sub-folder under E:\Program Files (x86)\LTC\LTspiceIV\lib\sym\

Best Answer

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:

Put the subcircuit in the sub folder
Put the symbol file in a directory of your choosing
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.

Related Solutions

Electronic – How to change the temperature of sub-circuits in LTSPICE

There are a few ways.

You can add it to the actual model you are using as a final parameter or use the component dialog box:

To get this dialog for anything that has a .model statement, use CTRL + right click.

If you are adding the temperature command within the SPICE listing, it needs the format of "temp=xx"; no dot required. The listing you show has omitted the '='.

Electronic – LTSpice D flip-flop not working

If you go to the LTspice help and navigate to "Special Functions" you'll see a list of parameters that can be selected for the digital components, including the Dflop.

Your shift register didn't work because it had no output rise or fall time associated with it, so everything was happening all at once!

Also, the digital stuff defaults to a Vcc of 1 volt.

I've redrawn your schematic so everything starts cleared, Vcc is 5 volts, and put some delay into the Dflops, and now it works. :)

If you right-click on any of the dflops, that'll bring up the attribute editor, which will show their edited (non-default) parameters, specifically:

SpiceLine = Vhigh 5 Trise 10n

and will allow you to modify any of the component's editable attributes.

Here's the schematic and the plot, which I edited to look like a timing diagram:

and here's the circuit list:

Version 4
SHEET 1 1732 752
WIRE 48 -144 -256 -144
WIRE 352 -144 48 -144
WIRE 656 -144 352 -144
WIRE 864 -144 656 -144
WIRE 1104 -144 864 -144
WIRE 1360 -144 1104 -144
WIRE 1616 -144 1360 -144
WIRE -128 -64 -368 -64
WIRE 176 -64 -64 -64
WIRE 480 -64 240 -64
WIRE 784 -64 544 -64
WIRE 864 -64 864 -144
WIRE -256 0 -256 -144
WIRE 48 0 48 -144
WIRE 352 0 352 -144
WIRE 656 0 656 -144
WIRE 1104 0 1104 -144
WIRE 1360 0 1360 -144
WIRE 1616 0 1616 -144
WIRE -368 48 -368 -64
WIRE -336 48 -368 48
WIRE -160 48 -176 48
WIRE -64 48 -64 -64
WIRE -32 48 -64 48
WIRE 144 48 128 48
WIRE 240 48 240 -64
WIRE 272 48 240 48
WIRE 448 48 432 48
WIRE 544 48 544 -64
WIRE 576 48 544 48
WIRE 1024 48 736 48
WIRE 1280 48 1184 48
WIRE 1536 48 1440 48
WIRE 1728 48 1696 48
WIRE -336 96 -368 96
WIRE -128 96 -128 -64
WIRE -128 96 -160 96
WIRE -32 96 -128 96
WIRE 176 96 176 -64
WIRE 176 96 144 96
WIRE 272 96 176 96
WIRE 480 96 480 -64
WIRE 480 96 448 96
WIRE 576 96 480 96
WIRE 784 96 784 -64
WIRE 784 96 752 96
WIRE 1024 96 992 96
WIRE 1280 96 1248 96
WIRE 1536 96 1504 96
WIRE -368 208 -368 96
WIRE 992 208 992 96
WIRE 992 208 -368 208
WIRE 1248 208 1248 96
WIRE 1248 208 992 208
WIRE 1504 208 1504 96
WIRE 1504 208 1248 208
WIRE -256 288 -256 144
WIRE 48 288 48 144
WIRE 48 288 -256 288
WIRE 352 288 352 144
WIRE 352 288 48 288
WIRE 656 288 656 144
WIRE 656 288 352 288
WIRE 1104 288 1104 144
WIRE 1104 288 656 288
WIRE 1360 288 1360 144
WIRE 1360 288 1104 288
WIRE 1616 288 1616 144
WIRE 1616 288 1360 288
WIRE -368 336 -368 208
WIRE -256 336 -256 288
WIRE -368 448 -368 416
WIRE -256 448 -256 416
WIRE -256 448 -368 448
WIRE -368 512 -368 448
FLAG -368 512 0
FLAG 864 -64 0
SYMBOL voltage -368 320 R0
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
WINDOW 3 86 297 Invisible 2
SYMATTR InstName V1
SYMATTR Value PULSE(0 5 1u 5n 5n 0.5u 1u)
SYMBOL voltage -256 320 R0
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
WINDOW 3 86 297 Invisible 2
SYMATTR InstName V2
SYMATTR Value PULSE(0 5 0 50n 50n 100n)
SYMBOL Digital\\dflop -256 0 R0
SYMATTR InstName A1
SYMATTR SpiceLine Vhigh 5 Trise 10n
SYMBOL Digital\\dflop 48 0 R0
SYMATTR InstName A2
SYMATTR SpiceLine Vhigh 5 Trise 10n
SYMBOL Digital\\dflop 352 0 R0
SYMATTR InstName A3
SYMATTR SpiceLine Vhigh 5 Trise 10n
SYMBOL Digital\\dflop 656 0 R0
SYMATTR InstName A4
SYMATTR SpiceLine Vhigh 5 Trise 10n
SYMBOL Digital\\dflop 1104 0 R0
SYMATTR InstName A5
SYMATTR SpiceLine Vhigh 5 Trise 10n
SYMBOL Digital\\dflop 1360 0 R0
SYMATTR InstName A6
SYMATTR SpiceLine Vhigh 5 Trise 10n
SYMBOL Digital\\dflop 1616 0 R0
SYMATTR InstName A7
SYMATTR SpiceLine Vhigh 5 Trise 10n
TEXT -352 480 Left 2 !.tran 0 30us 0

Best Answer

Related Solutions

Electronic – How to change the temperature of sub-circuits in LTSPICE

Electronic – LTSpice D flip-flop not working

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