Why do DC/DC switching controllers seem to favour the buck-boost topology over similar ones like Cuk, SEPIC and Zeta?
The Ćuk converter has an inherent inverting topology. This means if you feed a Ćuk converter with a positive input supply voltage it will produce a negative output voltage. This is a minority application hence it attracts fewer offerings in Digikey. However, the Ćuk converter has continuous input and output current capability hence it has an attraction (fewer emissions and output ripple) but, still it is &quot;inverting&quot; and uses two magnetic components (or one more complex coupled inductor).
If you swap the input inductor and MOSFET around, you can convert the Ćuk circuit into a Zeta circuit with the benefit that you get positive out for positive in but the input current is now going to be discontinuous in many applications. Compared against regular converters like buck and boost which can be operated with continuous input current (and use only one magnetic winding), the preference is to choose those devices.
As for the SEPIC, it also uses two wound components and, as pointed out for the other two types (Ćuk and Zeta) it uses two wound components. It also has a discontinuous output current and can be noisy when feeding poor output capacitors. The same can be said of boost converters but these only use one inductor.