LTC3769Recommended for New Designs
LTC3769 is a high performance single output synchronous boost converter controller that drives an all N-channel power MOSFET stage. Synchronous rectification...
Datasheet LTC3769 on Analog.com
There is no specific requirement that the inductor must is placed on the bottom side of the PCB. Assuming you are referring to LTC3769 DC2173A, it appears that placing the inductor on the back side resulted in a compact, easy to probe layout with tight input, output and hot loops.
