leo_o2
Advanced Member level 4
I have a similar guess as LvW. Possibly you got more than one loop in LDO. Some loop might be obscure. For multi-loop, you must make all loops have enough phase margin to make it stable. So probing AC characteristics at different places is needed.
Added after 18 minutes:
Would you post your schematic?
Added after 18 minutes:
Would you post your schematic?