MP2759 - What is the Purpose of Diode between Vin & PMID?

In the schematic, I see that there is a diode in between Vin and PMID. What is its purpose and is it required? I cannot seem to find it on the datasheet. Thanks.

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The diode between VIN and PMID is there to protect Q1’s body diode against high current. Q1’s body diode isn’t capable of sustaining high current, especially in-rush. This diode allows VIN to share the input current path between the diode and the Q1 body diode.