First of all, please provide your schematics and PCB layout in a "readable" format (e.g. pdf, or screenshot). I don't have SW to open your files, and I won't go search for it.
Edit 2: found the .pdf, at least there's the layout, but the schematic would be useful also.
So, that layout looks total crap (sorry, I don't intend to offend you, but it'll just won't work). Go and download all the documentation ADI provides for this chip, including the DC2117A manual and design files. They use a six-layer board to tame that beast. I don't think it's necessary to have a six-layer board, one should be able to get it working with a double sided board, but this requires a lot of experience to do it right in the first iteration. One must take care a lot of attention to the high power path, e.g. the high-side and low-side MOSFETs must be mounted close together and the switching node must have as short as possible traces between these MOSFETs, and so on ...
Next, with these IC's it's very common to blow them up easily. In most cases, the reason for them to release the smoke is an overvoltage transient on one or more of their pins. And with such HV IC's, theres very little margin from working to blowing up. Such transients easily happen due to not enough input filtering or bad layout. Unwanted inductance (e.g. due to too long and narrow traces) cause "inductive kickback" by turning off the current, that may happen on the input side of the IC. The switching node might ring too much, that might cause overvoltage here.
Another reason might be the inductor core saturating. This makes the current rise faster, even fast enough for the controller IC not being able to turn off the high side switch fast enough to prevent damage, or turning it off fast enough to save the MOSFET but causing a transient voltage at the input that in turn blows up the IC.
In general, one wants solid ground planes, short and wide traces for the power traces and heavy decoupling at the input side. A ceramic cap alone here will ring with the inductance of the supply leads and blow up the IC at turn on, so always have a combination of ceramic (for low impedance decoupling) and electrolytics (for bulk energy storage and damping) at the input node.
Edit: Anyway, where's the second MOSFET? Can't see one in the board photo.
Edit 2: Now I can see it, looks way too small.