I tried to make the graph of peak to peak output voltage vs input frequency for a custom designed opamp but the issue is when you use ac anaylsis it operates as small-signal so it does not care about rails. I intended to create such a graph below

 

hi Arda,
Welcome to AAC.
Please post your LTSpice asc file.
E

 

I intended to make a graph of Max(Vout)-Min(Vout) vs frequency, thanks for your help

 

hi Arda,
Attempted a simulation, a number of errors need to be corrected, ref this text file.
E

 

I tried to make the graph of peak to peak output voltage vs input frequency for a custom designed opamp but the issue is when you use ac anaylsis it operates as small-signal so it does not care about rails. I intended to create such a graph belowView attachment 357091

I would imagine that a dominant factor in that graph is the effect of the maximum slew rate.