The capacitor on the VC pin becomes the capacitor for the phase compensation circuit. If this capacitor is changed to a large constant, the response characteristics of the loop will deteriorate, so it is thought that the convergence to the target output voltage will be delayed and the operation will become unstable.

For the optimum value, measure the phase margin of the feedback circuit using a frequency characteristic analyzer (FRA) and adjust the circuit constants so that the margin is 60°.