This picture shows the typical circuit and components required for the DC/DC converter design. For this particular example, part BD9B301MUV-LB is chosen. All other parts in the BD9x series have a similar application circuit. Input, output capacitors, and inductor values are calculated based on input voltage, output voltage and necessary output current. The device datasheet shows an example of how these values are calculated. Feedback resistors are chosen to provide stable output voltage desired by the design. The equation to calculate these resistors is also given in the device datasheet.