I'm using LMR10515Y. It has a regulated 5.0V input and is setup for 3.3V output. The nominal current draw is around 400mA. Cin and Cout are 22uF ceramic. Inductor is 2.7uH. Most of the time the output is stable. On occasion at power up, the output will have a very fast dip to below 2V. This repeats every 760mS. This will cause the microcontroller to keep resetting.