When the switch is enabled, the output capacitors must be charged up from 0 V to VIN voltage. This charge arrives in the form of inrush current. Inrush current can be calculated using the following equation:

The TPS22916x offers multiple rise time options to control the inrush current during turn-on. The appropriate device can be selected based upon the maximum acceptable slew rate which can be calculated using the design requirements and the inrush current equation. In this case, the TPS22916C provides a slew rate slow enough to limit the inrush current to the desired amount.