BQ25798: BQ25798 and buck-boost mode

Tool/software:

Hello,

I need some specs at my project:

 - 2S Li-Po battery =  7,4V

 - Vin = 5-20V

 - VSYS 18 V

Can I use BQ25798 to generate VSYS = 18V ? Buck-Boost works to generate 18V with and wthout Vin?

Thanks,

Lucas.