My customer is using TPS7A47-Q1 and recently reports 5 failure cases (in total 30 boards).
1) Input voltage: 24.5~28V (Input comes from the multi-windings Flyback, it's the aux-winding output and varies due to cross regulation).
2) Output voltage: 24V
3) Output load current：0.02A~0.33A
4) As descried above, the input varies due to cross regulation. If the main output of the flyback is in full load, then this aux-winding can output 28V/0.02A. If the main output of the Flyback is in light load, then this aux-winding can output 24.5V/0.33A.
1) The failure shows TPS7A47-Q1 has output when load > 0.02A
2) If disconnecting the load, the failure shows lower output (output @21.5~23V, but can't achieve 24V)
3) Test if NG samples has short circuit between pins (Input & GND, Output & GND, Input + & Output), the answer is no short circuit.
4) A-B-A test shows the failure follows the NC samples.
Here is the schematic. Have you heard similar failure from other customers? Do you know what can cause this kind of failure? I am not sure if we need to submit a FA request.