We use this design on out board to create the internal voltage of the FPGA, it is set to 1.2V
On a few board we get about 1.7V output and the regulator isn't switching, it only switches at startup until it reaches 1.2V, the regulator stops switching and the output keeps rising until 1.7V
The first capture is zoomed in on the first part of the second capture
The yellow line is Vout, the blue one is Vswitch (pin7)
VCC is 3.3V
There are over 100 boards where it works perfect, but there are e few boards where we have this same problem.
What could be the cause of this failure?