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Help with LTSpice Op-Amp Modelling

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noobeestudent

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Hello guys, I'm in need of urgent help.

For my assignment, I was required to model an Op-Amp using a Behavioral Voltage Source using LTSpice.
The input resistance of the Op-Amp is 70MΩ and output resistance is 30Ω. The open loop voltage gain is 80k and the supply voltages is +-15V. I'm having problems with the behavioral voltage source. This is what I got so far.
1603015225516.png

Can anyone help me? Thank you in advance.
 

E.g. :

1603019101849.png


By the way, did you study the behavioral OP models shipped with LTspice, ipamp, opamp2 and universalopamp2?
 

Thanks for the help.
By the way, did you study the behavioral OP models shipped with LTspice, ipamp, opamp2 and universalopamp2?
I did learn to use those but I was asked to use the behavioral voltage to model the op-amp in this assignment
 

I need help again. I am supposed to use the above op-amp model to create a non-inverting amplifier with a gain of 40.
1603113687205.png

This is what I have now. But the syntax for the behavioural voltage source does not work. What does it need to be?

Edit: Ive figured it out, changed it to "V=limit((V(Vi)-V(Vx))*80k,-15,15)" and it worked.
 
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There's a nice online help, why don't you read it?

Wrong node voltage syntax, write either V(Vi,Vx) or (V(Vi)-V(Vx)).
 

Using this op-amp model , i have to integrate these extra conditions
  • Unity gain bandwidth = 10MHz
  • Frequency response roll-off rate = 20 dB/dec

1603119175456.png


Does anyone knows how to implement those into the op amp model?
Any help is very much appreciated. Thanks a lot.
 

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