Thank you for these comments and agreed, I would also think that one must use the TPS62933F to implement a Flybuck.
Do you have a reference design that the customer could use as a starting point for:
Vin= 12V ... 28V, Vout=5V, Iout=100mA
As we talked offline, we may have some actions here:
1. Use TPS62933F to check whether there is any noise here.
2. Capture the output voltage during load transient
3. Check the output cap voltage tolerance.
You may also try to add one Cff here…