I'm dealing with an existing design that utilizes multiple TPS545672. A small percentage of hardware exhibits what to be latch up characteristics after a input power drop out for a few hundred milliseconds. During this Dropout the VIN power input to the TPS54672 will drop to near zero but the Voltage reference REFIN is derived from will remain at the nominal level. The dropout transient causes, the TPS54672 REFIN pin to draw excess current causing the REFIN voltage level to to droop and the output voltage to droop (about -40%). If power is cycled for a longer period the hardware recovers.
Is this expected behavior? Only A small percentage of the hardware exhibits this issue.
The cause and symptoms both seem to point toward the device latching up. Are there any likely causes for this issue, that I would want to consider before pursuing this as a latch up problem?
