TPS74801: TPS74801

Part Number: TPS74801

Hello,

 have question regarding a power designer simulation using a TPS74801.

My Power Designer settings as following: Vin_min=1.69V; Vin_max=1.71V; Vout=1.5V; Iout_max=0.5A;Max Ambient 55C. 

I would like to set Vbias to 3.3V, to match my intended design configuration. For some reason the lowest value that available is 3.5V. 

Question, Why the lowest Vbias value is 3.5V? According to the part spec, a voltage applied to the Vbias pin could be as low as Vin + 1.65V. Even, as I understand that is not a recommended configuration.

Also, do you see any issues with my configuration?

Regards,

Alex