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LM76003: Issue with varying output voltage

Part Number: LM76003

I am using an LM76003 as a 28V to 5V converter.  It has been in the design under consideration for a few years, having undergone 3 separate build cycles (in other words, 3 lots of boards have been built using the same design over the past couple of years)

The last two runs have had issues with roughly 30% fallout with the following symptom:

The output voltage of the +5V regulator will change based on power-cycling the board.  I see up to about 0.2V delta between min and max output voltage for units that exhibit this behavior.  The +5V output seems regulated, but the absolute value changes almost with every power-on event, staying the same voltage while powered on.  For example it will power on at 5.05V, 5.12V, and 5.20V.  It seems to usually hover near a discrete set of output voltages, but again the voltage output changes usually with each power-cycle applied to the board under test, but once powered on, the output voltage is stable at whatever "random" voltage it came up with.

The other 70% of the units always start and run at the expected voltage of 5V +/- about 2%, based on the design having 1% feedback resistors.  The output voltage of these units always comes up within 1mV from power-on to power-on.

All parts in this batch of boards have markings "TI 93J P42X G3"

Thanks for any ideas,

Will