Some more documentation deficiencies:
And some layout comments. I think. Again, can only guess at what/where a lot of components are.
![help with buck regulator pcb](https://www.eevblog.com/forum/index.php?action=dlattach;topic=435947.0;attach=2330749;image)
Spend time studying the datasheet/appnote layout -- appnotes in general are poor, but they're at least a starting point to go from. Keep in mind that distance, trance length, body length, all count against you in terms of stray inductance. You *will* see switching noise everywhere, because everything is coupled into the main switching loop: long grounds to few (mostly single!) vias means lots of nH's add up (figure ballpark 0.5nH/mm). Use wide connections, lots of vias, especially when stitching top side to GND.
Maybe some ceramic caps on the output would be desirable too, I don't know.
The mostly solid bottom ground plane will help greatly with common mode, but do try to avoid trace length there, and when unavoidable, try to space traces so that ground can fill between them (and further, pour top side with GND and stitch that over the gaps made by bottom-side traces). R29/C46 is especially egregious in this regard, crossing under the main switch node itself (I think), and thus preventing that node from having solid uninterrupted ground under it.
Tim