The MP5014A is a protection device designed to protect circuitry on the output (source) from transients on the input (VCC). Also, it protects VCC from undesired shorts and transients coming from the source.
At start-up, the inrush current is limited by restricting the slew rate at the source. The slew rate is controlled by a small capacitor at DV/DT. DV/DT has an internal circuit that allows this pin to float (no connection) and still receive 1 ms ramp time at the source.
The maximum load at the output is current limited. This is accomplished by utilizing a sense FET topology. The magnitude of the current limit is controlled by an external resistor from I-LIMIT to SOURCE.
An internal charge pump drives the gate of the power device, allowing a very low on-resistance DMOS power FET of just 36 mΩ.
The source is protected from the VCC input going too low or too high. Under-voltage lockout (UVLO) assures that VCC is above the minimum operating threshold before the power device is turned on. If VCC rises above the high output threshold, the source voltage is limited.