In order to generate Bode plots in PSpice, you need to follow several steps as described below:
place a VAC voltage source in your circuit, wherever you want to inject the AC signal (it is floating, usually in series with the feedback loop of interest, location is also important)
The default 1V AC and 0V DC is recommended so the ratio of the two signals used in Bode plot will require no additional adjustment
name the two nets connected to AC source e.g. 'in' and 'out', signal direction is important
Under PSpice→Edit Simulation Profile→Analysis→Analysis type, select AC Sweep/Noise and define the frequency range (typ. 10m to 1G)
Run the simulation
In AMS Simulator window, Add Trace and select from Functions or Macros the 3rd option, Plot Window Templates
In the drop-down menu, thereare several options to pick; I usually prefer Bode Plot dB - Separate(1)
replace 1 with V(out)/V(in); the Trace Expression would look like this: Bode Plot dB - separate(V(out)/V(in))
Most of the time this 'direct' method works ok but in case of issues, try the so called Middlebrook's method:
'out' node connected to VAC via a huge capacitor, e.g. 100kF
the other terminal of VAC connected to ground or '0' node
'in' node connected to 'out' node via a huge inductor of the same value
This way, in DC, the AC source is virtualy disconnected from the circuit while the feedback loop is still closed.
I am also facing the same problem as you, does anyone here have a solution?
retro bowl
In order to generate Bode plots in PSpice, you need to follow several steps as described below:
Most of the time this 'direct' method works ok but in case of issues, try the so called Middlebrook's method:
This way, in DC, the AC source is virtualy disconnected from the circuit while the feedback loop is still closed.