Other Parts Discussed in Thread: TPS51200
Greetings. We have a DDR4 TPS51200 legacy design with ~25uF on REFOUT. The latest datasheets recommend <0.47uF. There are various posts recommending legacy design are okay with a higher loading on REFOUT, though most of those recommendations are on designs with <25uF. We've had a few scenarios where we've failed board test only to find REFOUT at 0.4V while REFIN was at 0.6V, LDOIN at 1.2V, and VIN at 3.3V. In these scenarios Vtt was not verified but I would assume it matches REFOUT. It's suspiciously close to REFIN UVLO. Is it possible that the loading on REFOUT causes instability that damages the device? In the failed boards we reduced the REFOUT capacitance only to find REFOUT still at 0.4V. Any and all feedback/recommendations are welcome.