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How can I change in LTSpice 555timer frequency??

Vugar

Apr 15, 2022
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Hi Everyone. I bought NE555P 500KHs. Had some experiments in oscilloscope. Wanted to compare oscilloscope results with Simulation results but there is big problem. In software program(multisim and LTspice) which I use This timer frequency is different, how can I solve this problem in simulation part??

There are link where I bought that 555 timer and I upload my circuit below.
https://www.tme.com/us/en-us/details/ne555p/watchdog-and-reset-circuits/texas-instruments/
 

Attachments

  • ne555.asc
    1.8 KB · Views: 6

Alec_t

Jul 7, 2015
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In software program(multisim and LTspice) which I use This timer frequency is different, how can I solve this problem in simulation part??
Which Spice model of the 555 are you using? The default model that comes with LTspice is an idealised one, so will not give a true-to-life simulation result.
Welcome to EP!
 

crutschow

May 7, 2021
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May 7, 2021
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Do you have any other 555 models in LTspice?
If not, you need to download the 555 transistor model, which I can post if you want.
 

Vugar

Apr 15, 2022
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Apr 15, 2022
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Which Spice model of the 555 are you using? The default model that comes with LTspice is an idealised one, so will not give a true-to-life simulation result.
Welcome to EP!
Is there any program that you can suggest for simulation. I use multisim and LTSpice both of them giving the same result which is not near the oscilloscope results.
I use in practical texas NE555P 500KHs
https://www.tme.com/us/en-us/details/ne555p/watchdog-and-reset-circuits/texas-instruments/
 

Alec_t

Jul 7, 2015
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I use multisim and LTSpice both of them giving the same result which is not near the oscilloscope results.
Can you post both your LTspice .asc file and a schematic of the actual circuit in which your 555P is being used?
What load is the 555P driving?
What oscilloscope results are you concerned about? How is your scope configured and connected?
 

crutschow

May 7, 2021
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May 7, 2021
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Here are the 555 transistor model files.
I had to zip them since this website, in their infinite wisdom, won't allow me to download LTspice model files.
The .sub file goes in the LTspice lib/sub folder, and the .asy file goes in the lib/sym/misc folder.
 

Attachments

  • NE555-1 (2).zip
    653 bytes · Views: 2
  • NE555-1.zip
    446 bytes · Views: 2

Alec_t

Jul 7, 2015
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What tolerances do your real-life timing components have?
 

crutschow

May 7, 2021
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Yes, you must consider the tolerance of the real components you use.

The NE555-1 model I posted should give close to the real timing values if you include the various tolerances in the simulation.
 
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