I have a design with 3 TPS54360 on one Board: 12V, 5V and 3,3V
The Input Voltage is about 38VDC. When I switch off the Input Voltage it ramps down for about 300ms to a Voltage of around 4V.
Then the 3.3V Regulator shuts off the Output.
Approximately 100ms later the Regulator starts again for around 2ms (up to 3V) and another 500ms later it generates another spike!
The behaviour decreases when I lower the Input Voltage. At around 15V the problem does not persist any more.
You can imagine that a Processor module tends to ruin certain memory cells when confronted with such short pulses.
On the oscilloscope it seems, that the Input Voltage drops below 4.3V and recovers again after the TPS54360 switches off. Then the IC starts over again.
Because of a rectifying input I have quite high capacitance on the input (3x470µF Caps). Do you think they recover
How can I improve this "hysteresis"?