The first step is to decide on a switching frequency for the regulator. There are tradeoffs to consider for a higher or lower switching frequency. A higher switching frequency allows for lower valued inductor and smaller output capacitors leading to the smallest solution size. A lower switching frequency will result in a larger solution size but better efficiency. The user will typically set the frequency for the minimum tolerable efficiency to avoid excessively large external components.

A switching frequency of 600 kHz is a good trade-off between efficiency and solution size. The appropriate resistor value is found from the resistance versus frequency graph of Figure 6-5, or calculated using Equation 1. R4 is calculated to be 78.4 kΩ and the nearest standard value resistor of 78.7 kΩ is selected. A resistor must be placed from the FREQ pin to ground, even if an external oscillation is applied for synchronization.