After enabling the device, there is a 650-µs enable delay (t_Delay) before the device starts switching. The t_Delay time varies with the VSET/MODE resistor used and is longest with a resistance of 249 kΩ or higher. After the enable delay, an internal soft-start circuit ramps up the output voltage in 1 ms (t_Ramp). This action avoids excessive inrush current and creates a smooth output voltage ramp up. This action also prevents excessive voltage drops of batteries that have a high internal impedance. Figure 7-2 shows the start-up sequence.

Figure 7-2 Start-Up Sequence

The device is able to start into a prebiased output capacitor. The device starts with the applied bias voltage and ramps the output voltage to the nominal value.