# Inductor for boost converter circuit

I'm using an AAT1217 for the boost converter in my circuit. The reference circuit I'm using is:

The datasheet suggests several inductors:

It suggests using these fairly large inductors, the ones that you can see the coils. My question is why aren't the normal 0402/0603/0805 SMD inductor packages being used instead? For example, the MLZ series from TDK has a similar DC resistance and a fairly large DC current rating of 500 mA. The fine print does mention that "Current assumed when inductance ratio has decreased by 50% max". When does the inductance ratio change?

Also, I've run some experiments with both the CR43 and the MLZ inductor and they are both able to drive the servo motor (MG90S) fine. Am I missing anything? Or is it perfectly fine to switch to a smaller, more compact inductor? (the other thing that I am wondering is if the AAT1217 datasheet was written a while back when small inductor packages did not exist).

• The most straightforward (and most useful) way to measure these losses is simply to measure the efficiency of the switching converter with the inductor installed. Exercise the converter over its $V_{in}$ and $I_{out}$ range for a more complete picture of what's going on. Whichever inductor yields best efficiency exhibits the least loss. – Zulu Apr 8 '15 at 0:56