Fortunately I came across this great Hackaday page by Patrick!
He was nice enough to answer questions and help me with my design. My previous 2 layouts were failures, shutting down after only <4.5W output.
I notice the recommended inductors for this thing are >4A! for only 2A output current I thought this was very strange..
Anyway, I designed this new proto board to run further testing. I'll report back!
So far I learned:
*CFF is not necessary. It is used for large transient load regulation. The recommended 10pf completely screwed up the output. A more modest 1pf seemed to work better (both 50v NP0 rated)
*Actual efficiency is closer 80-85%
*ILIM should be tied to EN if unused
*Ground loop layout is extremely critical
Questions I have so far:
Q: GND and PGND being separate makes me wonder if GND should be tied only to signal ground, i.e. the FB resistor? But the datasheet layout shows them joined so...that's what I did
Q: How will it funtion with a 3A-4A Inductor, rated 2.2uH?
Q: What is the actual sleep mode current draw?
Q: What is the EN pin current draw (wondering if a flip flop might actually be causing an issue driving this)