The device requires an input capacitor to reduce the surge current drawn from the input supply and the switching noise from the device. Ceramic capacitors with X5R or X7R dielectrics are highly recommended because of their low ESR and small temperature coefficients. For most applications, a 10-μF capacitor with an additional 0.1-µF capacitor from VIN to GND to provide additional high-frequency filtering is enough. The input capacitor voltage rating must be greater than the maximum input voltage.

In this design, a 10-µF, 35-V X7R ceramic capacitor is chosen. This yields around 40-mV input ripple voltage.