Input and Output Filtering

All DC/DC converters have an output ripple voltage due to the charging and discharging of the output capacitor with each pulse of energy from the internal oscillator. This output ripple has a frequency of either the same or double the main oscillation frequency, depending on the topology, and is typically in the 100-200kHz region. Superimposed on this ripple voltage are switching voltage spikes with a much higher frequency, typically in the MHz range.