I created a designed with components selected by WebBench a LMR16006 Simple Switcher that switches from 48V (V_in) to 5V (V_out). When I tested new boards I had assembled, I found that the output voltage was only 1.26, substantially lower than my desired 5V output. After some investigation, I found that the switching rate detected on SW (pin 6) is switching at around 150 kHz or so, much lower than the 700 kHz I should be seeing. I suspect that there's some sort of overload condition going on, but I can't figure out what is causing it -- I used all of the parts exactly from WebBench. My design and component values are listed below:
One potential cause is that my load is highly variable -- they're high power smart LEDs (integrated drivers), so if they're off, they draw a very low amount of current, but if they're on, then current draw can be up to 500 mA. The converter is designed for 500 mA max draw, but at startup the draw is quite low.
Otherwise, I'm having trouble finding out the root cause -- I've gotten one of my assembled boards to work, but just one out of five so far, so there seems to be some sort of instability that's causing the converter to shut down.
