I am trying to compensate a buck converter. I've set up an averaged model of a buck converter in LTSpice.
Here is a picture of the simulation. The B3 voltage takes into account the gain from using a 5 Vpp sawtooth wave for the comparator:
Note: L1 inductor has 210 mΩ series resistance. C1 has a 10 mΩ ESR. Inductor and capacitor values calculated @ 1 MHz operating frequency.
I have closed the loop at ~40 kHz with a target phase margin of 75 degrees. Here is a capture of the bode plot:
When applying an input voltage transient from 0-10 V on the input, the output voltage has some overshoot. With a phase margin of 75 degrees I would not expect the output to be overshooting as much as it is. I'm curious if there is something wrong with my simulation or the op amp itself? Note: V(n001) refers to the output voltage.