To minimize inrush current and output voltage overshoot during start-up, the device features a controlled soft start-up. After the device is enabled, the device starts all internal reference and control circuits within the enable delay time, T_delay. After that, the maximum switch current limit rises monotonically from 0 mA to the current limit. The loop stops switching once V_O is reached. This allows a quick output voltage ramp for small capacitors at the output. The bigger the output capacitor, the longer it takes to settle V_o. A potential load during start-up will lengthen the duration of the output voltage ramp as well. The gradual ramp of the current limit allows a small inrush current for no-load conditions, as well as the possibility to start into high loads at start-up.

Figure 9-4 Device Start-up Scheme