We have a board running RT1020.
The main power structure is 12V -> 3.9V SMPS, then this 3.9V is going through and LDO to 3.3V and then to RT1020.
See schematic attached for how it is connected.
The problem is that if we dip main voltage below the point where the SMPS drops and thus the 3.3V signal starts to flicker, and then increase voltage back up, the DCDC of the RT1020 does not start. All other voltages are fine.
Any thoughts? Could it be something regarding the RC circuit on the DCDC_PSWITCH for instance?
Any help if greatly appreciated.