A 1.44 W Universal Input Buck Converter
Check the design guide not just the datasheet. Many companies have information in app notes not just the datasheets and each company is different.
High side buck converters need not just the feedback path to be optimized but the inductor and capacitor as well. There is a an equation on page 10:
$$ R_{fb} = \frac{V_o - V_fb}{\frac{Vfb}{R_{bias}}+I_{fb}} $$
\$ R_{fb} \$ is R1 in the diagram and \$ R_{bias} \$ is R3, \$ I_{fb} \$ is 49uA