The choice of switching frequency is a compromise between conversion efficiency and overall design size. Lower switching frequency implies reduced switching losses, resulting in higher system efficiency and less power dissipated in the converter. However, higher switching frequency enables the use of smaller inductors and capacitors, enabling a more compact design.

Many automotive applications require that the AM radio band be strictly avoided. Such applications tend to operate at either 2.1MHz or 400kHz, above and below the AM band, respectively. To achieve small design size set the LM63440-Q1 or LM63460-Q1 switching frequency at 2.1MHz for this application example by installing a 6.04kΩ resistor from RT to GND.