LT3922 Buck Mode LED Driver

Hello LT Support,

 

 

I want to use the LT3922 in Buck Mode as an LED Driver for a 12V/1,5A LED (one power LED). The supply voltage is 15V. Additionally I want to use the SSFM option with up to 2MHz switching frequency (base fsw=1,6Mhz*125%).

 

The goal is to achive very low noise EMI on PCB Level.

 

Will this application be possible without any issues with the mentioned configuration?

In the datasheet there is an example application (added as attachment). What exactly does the Q1 pnp do? A detailed answer in connection with the functional sequence would be great  

 

Any advices, like which filter to add to the output/ input or which changes to apply to the example application are appreciated a lot. 

 

Thank you!
Max K.