Make sure the ESR zero frequency of the
capacitors used is at least 5 × the expected crossover frequency. This way, the impact of
the ESR on the loop gain is reduced to a manageable level.
Equation 7.
The amount of output capacitance has a
direct impact on the closed loop bandwidth of the converter. Too little capacitance and
the bandwidth can be too high to maintain stability.
The amount of output capacitance has a
direct impact on output voltage overshoot during a load drop. Too little capacitance and
the stored energy in the output inductor can cause the output voltage to overshoot during
a sharp load decrease.
The impedance of the output capacitance
(impedance of the capacitors plus ESR) has an impact on the output ripple noise of the
converter. Too high an impedance (due to not enough capacitance, too high ESR, or both)
can result in output ripple above system requirements.