LTSpice and CD4013

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Jony130

Joined Feb 17, 2009
5,488
Hi, I have a question.
Why this circuit do not work as expected?
schmitt.png

As you can see I set-up 4013 as a non-inverting buffer with hysteresis.
But this circuit do not work in LTspice only circuit with the 4049 gates work. Do anyone knows why is that ?
 

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crutschow

Joined Mar 14, 2008
34,414
.........As you can see I set-up 4013 as a non-inverting buffer with hysteresis........
But you haven't.
CLR is constantly high so the Q output is constantly low.

But, the real problem is, CD4013 can't be configured as a non-inverting buffer.
Why/how did you think it could be?
 

Thread Starter

Jony130

Joined Feb 17, 2009
5,488
But, the real problem is, CD4013 can't be configured as a non-inverting buffer.
Why/how did you think it could be?
But in real life this circuit work as a non-inverting buffer with hysteresis .
Take a look at CD4013 data sheet
CD4013.png
http://www.ti.com/lit/ds/symlink/cd4013b-mil.pdf
https://www.nxp.com/documents/data_sheet/HEF4013B.pdf
http://www.onsemi.com/pub_link/Collateral/MC14013B-D.PDF

CLR is constantly high so the Q output is constantly low.
This might be the case in LTspice.
 

Robin Mitchell

Joined Oct 25, 2009
819

crutschow

Joined Mar 14, 2008
34,414
Yes, it would appear that the LTspice model doesn't properly simulate Q going high when both the PRE and CLR are high, which is not a typical operating configuration.
 

eetech00

Joined Jun 8, 2013
3,942
Hi

Back in 2013, an issue with the 4013 was identified that as since been corrected in the library file.
I think your using an old version of the CD4000.lib file.

The OPs asc file works on my system

4013InvBuffer.png
 

Thread Starter

Jony130

Joined Feb 17, 2009
5,488
OK, I manage to download a new library file. And now everything work as it should

Voltage on PRE (S) input in LTspice
11.png

And the same voltage on pin S (PRE) measured in real circuit via Rigol.

NewFile37.png

Thanks to all for your help.
 

hsc

Joined Dec 21, 2016
1
Hi all,
I tried to start this simulation too, but LT spice has problems to open the lib. Whats wrong with the lib? Or is there a special setting necessary?
 

ScottWang

Joined Aug 23, 2012
7,399
Hi all,
I tried to start this simulation too, but LT spice has problems to open the lib. Whats wrong with the lib? Or is there a special setting necessary?
Download the file CD4000_v.lib that I attached in #11, and put into the directory as sym where you installed the LTspice software, and open the CD4013_onoff.asc, when the error occurring then go to modify ".include cd4000.lib" and using the browser to find the CD4000_v.lib where does it located as above described.
 

eetech00

Joined Jun 8, 2013
3,942
Hi all,
I tried to start this simulation too, but LT spice has problems to open the lib. Whats wrong with the lib? Or is there a special setting necessary?
The CD4000_v.lib file should be located in the schematic folder or the program installation folder LTspiceIV\lib\sub".
Then place the following directive on the schematic: ".inc CD4000_v.lib" without the quotes.
You must place a voltage source with a VDD label on the schematic to provide the internal supply voltage to the component, or an error will occur.
 
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