LTspice replacement 555 model?

Thread Starter

ElectricSpidey

Joined Dec 2, 2017
729
Ok, so I finally broke down and installed LTspice and of course the first thing I needed was the 555, but the model that comes with LTspice is really dorkey…I mean how do you lay out a proper schematic with that thing.

So my question is…

Does anybody here have a proper model, something that matches most normal schematics? Or know where I can get one? Or even create one?

Like this…

Vss and CV at the bottom.

Vcc and Reset at the top.

Discharge, Threshold and Trigger on the left…in that order, with the proper spacing to just drop in the resistors without creating a spaghetti monster.

And the output on the right.
 

dl324

Joined Mar 30, 2015
9,121
I mean how do you lay out a proper schematic with that thing.
Readable schematics isn't its strong point. You should be able to make your own symbol.

If you really want to draw readable schematics, get a real schematic editor. I use Eagle and had to create my own timer symbol:
upload_2018-5-29_18-43-30.png
My version of Eagle won't let me rotate pin text...
 

ebp

Joined Feb 8, 2018
2,332
You're just too fussy!

Actually, I totally agree with you. In my schematic libraries I probably have at least three variants of the 555 to allow doing exactly as you suggest for different config's. I have at least three variants each for NPN and PNP transistors. The list goes on. Almost every time I did a new project with a microcontroller I would create a new variant of the schematic symbol so I could make nice neat schematics with well-ordered functional grouping of I/Os. You wind up with bigger rectangles for the ICs, but actually denser, neater, more readable schematics.

Sorry, I don't use LTspice, so I can only commiserate.
 

eetech00

Joined Jun 8, 2013
1,715
Ok, so I finally broke down and installed LTspice and of course the first thing I needed was the 555, but the model that comes with LTspice is really dorkey…I mean how do you lay out a proper schematic with that thing.

So my question is…

Does anybody here have a proper model, something that matches most normal schematics? Or know where I can get one? Or even create one?

Like this…

Vss and CV at the bottom.

Vcc and Reset at the top.

Discharge, Threshold and Trigger on the left…in that order, with the proper spacing to just drop in the resistors without creating a spaghetti monster.

And the output on the right.
Hi
You mean like this?

NE555CustomSymbol.png

Here's the files...
 

Attachments

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Thread Starter

ElectricSpidey

Joined Dec 2, 2017
729
It's late here so I need to get to bed, but one question, then I will install after work tomorrow, and let you know how it went.

The zip has 3 files, can you tell me which folders they belong in.

I assume the .asc goes in the default folder located in my "user" folder, but I don't know where to place the other 2.
 

Alec_t

Joined Sep 17, 2013
10,438
With version XV11 and Win10, LTS looks for model files (.sub) in your Documents/LTspiceXV11/lib/sub folder and looks for the symbol (.asy) in an appropriate sub-folder (e.g. Misc) of your Documents/LTspicXV11/lib/sym folder. The .asc file can go wherever you want.

Btw, you can edit any LTS-originated symbol by opening its .asy file in LTspice and save the edited version. Be aware, though, that an LTS update will probably revert the symbol to its 'official' form unless you changed the file name when saving.
 
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eetech00

Joined Jun 8, 2013
1,715
With version XV11 and Win10, LTS looks for model files (.sub) in your Documents/LTspiceXV11/lib/sub folder and looks for the symbol (.asy) in an appropriate sub-folder (e.g. Misc) of your Documents/LTspicXV11/lib/sym folder. The .asc file can go wherever you want.

Btw, you can edit any LTS-originated symbol by opening its .asy file in LTspice and save the edited version. Be aware, though, that an LTS update will probably revert the symbol to its 'official' form unless you changed the file name when saving.
The custom symbol already has a unique file name so should be unaffected by an LTspice update.
 

eetech00

Joined Jun 8, 2013
1,715
Windows 7

The three files in the zip are…

(.asy)
(.asc)
(.plt)

I don’t see a (.sub)

(haven't unzipped the files yet)
Different users manage their files differently. Some users like to place the new files in the stadard library location. Unzip the file, then move the .asy file to the folder location described in post #9 (Misc). The symbol can then be selected by opening the LTspice component selector and navigating to the MISC folder. You should see a symbol named NE555-1.

The other files do not need to be moved or changed. The .asc file is the schematic. The .plt file is the saved plot configuration file.

However, the ".lib NE555.sub" statement will be needed on the schematic where the symbol is used.
To avoid this, open the NE555-1 symbol in LTspice, then edit the "spicemodel" attribute to contain "NE555.sub", without the quotes. Now you'll be able to use it on any schematic without placing the ".lib NE555.sub" statement on the schematic.

If you just want to quickly run the schematic simulation as is, unzip the .zip file, browse to the upzipped folder, then double click the .asc file. These actions should launch LTspice and open the schematic file. Then click the "running man" symbol on the menu bar to start the simulation.

eT
 
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Thread Starter

ElectricSpidey

Joined Dec 2, 2017
729
Great, thanks again.

Ok, let me see if I have this straight…

A “symbol” and a “model” are two different things…correct?

The file you posted is a “symbol” that uses the default ideal model…correct?

I know this really doesn’t mean anything to anybody else but, I created a “Spideys_Models” folder placed the symbol file in there and then registered the path in Control Panel, and now I can see the symbol in the components drop down box.
 

eetech00

Joined Jun 8, 2013
1,715
Great, thanks again.

Ok, let me see if I have this straight…

A “symbol” and a “model” are two different things…correct?
Yes
The symbol is a graphical representation of the component. This is the .asy file

The model defines the behavior of the component. This is the .sub file and the .sub file extension is recognized by LTspice. But any extension can be used.

The file you posted is a “symbol” that uses the default ideal model…correct?
Yes

I know this really doesn’t mean anything to anybody else but, I created a “Spideys_Models” folder placed the symbol file in there and then registered the path in Control Panel, and now I can see the symbol in the components drop down box.
Congrats!!
Your on your way to understanding LTspice!!

eT
 

Poita

Joined Dec 1, 2019
1
Hi guys, thanks for the symbol, I've downloaded and copied the .asy file to the relevant folder, and added the ".lib NE555.sub" statement to my schematic, but on trying to run my design I get the following error:
"Port(pin) count mismatch between the definition of subcircuit "ne555" and instance: "xu1". The instance has more connection terminals than the definition".
I'm at a loss as to how to solve this? Any ideas?
 

eetech00

Joined Jun 8, 2013
1,715
Hi guys, thanks for the symbol, I've downloaded and copied the .asy file to the relevant folder, and added the ".lib NE555.sub" statement to my schematic, but on trying to run my design I get the following error:
"Port(pin) count mismatch between the definition of subcircuit "ne555" and instance: "xu1". The instance has more connection terminals than the definition".
I'm at a loss as to how to solve this? Any ideas?
Hi

Upload your schematic....then we'll take a look.

eT
 
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