9.2.1.2.2 Output Capacitor Selection

A ceramic capacitor with a 100-V voltage rating is recommended for the output capacitor. The DC-bias effect can reduce the effective capacitance by up to 80%, a consideration for capacitance value selection. Effectively the capacitance must be 33 µF for 600-mA loads. A different option is to use an aluminum electrolytic capacitor with low ESR and ceramic capacitor in parallel. Typically a 33-µF (ESR < 500 mΩ) with 10-µF (effective) ceramic capacitor in parallel is sufficient. If ESR is lower, capacitance for ceramic capacitor can be decreased.

For higher switching frequency (2.2 MHz) and boost output current below 400 mA, two 10-µF ceramic capacitors in parallel are sufficient.