LM25119: What limit the output current?

Part Number:LM25119

Hi,

From TI.com, can see the Iout(max) of LM25119 is 40A.

As I know, the current limitation is all about MOSFET and Inductor, am I right?

Here are the question:

1. How this 40A be defined?

2. What limits the output current?

3. Can I use it support 40A+40A?

Thank you.