The MP5013A is a protection device designed to protect circuitry on the output (source) from transients on the input (VCC). Also, it protects the input from undesired shorts and transients coming from the source.
A small capacitor on DV/DT controls the slew rate that limits the inrush current at the source. DV/DT has an internal circuit that allows the customer to float this pin (no connection) and still receive 1.4 ms ramp time at the source. The maximum load at the source is current limited using a sense FET topology. An external resistor between I-LIMIT and SOURCE controls the magnitude of the current limit.
An internal charge pump drives the gate of the power device, allowing the DMOS power FET to have a very low on resistance of just 36 mΩ.
The MP5013A protects the source from the input becoming too low or too high. Under-voltage lockout ensures that the input remains above the minimum operating threshold before the power device turns on. If the input rises above the high output threshold, the MP5013A limits the source voltage.