Would a shielded inductor be probable? Or is that type all ready in use?
Or an non shielded type?
As for the shield (the "metal box" ) that sets close or at the switching node area would be based on at least 2 factors of concern, 1 I doubt the current switch noise would be too great to flood the added metallic component (depending of material) and cause problems, however, be careful that the add on part in size does not ( for the better term I can use that fits close to what I'm trying to say) The term "saturate" and produce an antenna like effect to the surrounding area (this should not happen unless large startup spikes are possible). That is unless the shield would be non conductive at its uppermost top and sides (coated) and only the bottom plate exposed and the soldered point for conduct. Or be greatly adequate at allowing the flow to the quiet plane on the board enough to not need concern about coating the shield at all.
2. And that the shield does not reflect back causing amplification of noise.
: Edit : add in the term, reactance.
Most point, that added shield would reduce noise as long as the out is directed towards the PCB input common or large enough plane area that can accept and result in an ignore the noise ( it has little to no problem accepting the noise) value.
Do not see a ferrite solution on that a compact space, however if possible to round out the trace a tad located by the what should be the larger value 2nd capacitor above the inductor on the output side onto the plug via to one of the innermost layers. (added an image below showing 2 areas only focusing at the inductor) and commutation diode anode. The minor issue at the commutation diode could be ignored as it would not be an at all times issue, start ups and shutdowns and unstable power inputs from grid that rate a major drop in power or ramp that might affect the switch.
Any MOV type device would handle the ramp up from grid as will an ICL at main input.
That's just the thing with inductors, that both sides are not an absolute value when switched adequately, I'm referring to the inductor out, if there is a returned "ripple" effect the inductor core would be strongest at what value it is being charged to so to speak, and the nano and uF range capacitors are to stabilize the voltage to a percent on the inductor output, if the output has a chance to back feed, the voltage can begin to fluctuate enhancing ripple and show itself at the switching side in a minor sense as there can be a delay before the switch in sinking mode would see this, all ready changing to source mode causing a minor collision at the inductors input from switch causing an odd ramping voltage noise.
Some affects that have this issue tend to adjust the value of inductor to try and match this return ripple and create a matching or close to collision at inductors output that the capacitors absorb the unwanted value when a board design encounters this issue rather than a complete or possible need to redesign the PCB if the problem is too fast for a capacitor (term rare). Other directions to take are on the capacitors ESR rating can alter things considerably. Tho that can be tasking to find an reasonable value and whilst compensating for temperature if that is a requirement, minor core changes with temperature that can take that effort to find that best placement of value and just thrash it by a few points in either direction of temperature resulting in a no longer adequate setting.
I'm still grasping at these concepts, and as to why i went for the MIC5156 because of the voltage issues that I had with EZ buck converters of all things...
Hope this is somewhat helpful. I just lack comprehension at times unless I'm holding an board in front of me explaining in person... I just don't get why I have issues transferring this to text often more than...
And yet it should be simple .. I'm the one thinking it as I type. lol.