Inductor selection always confuses me. There is a spec for inductors as self-resonant frequency. For example, on digikey, as SR frequency of inductors increase, the price may increase or decrease. But why? See this graph below, behavior of self resonant frequency response of the inductor:
Assume we have a circuit board with SMPS has switching range in between 1-2 MHz and a few other analog blocks work in up to 4 MHz. In this case, is it smart to use an inductor with SR frequency below 1 MHz or over 4 MHz? And why?