Hello
One of our products that use TPS51216 as a memory power solution, started to face VTT stability issues resulting in start up failure. The symptom shows after about of 10 system power cycles, and disappears only after 30 minutes of power loss. The issue can be observed in about of 10% of all the units, and started to appear after about a year of a system usage. A PGOOD rails is not rising up at all, or shows a short spikes while VTT at their lowest point.
Attached VTT ramp up scope screen shot and PGOOD spike. There is no issues with main VDDQ rail.
I'll appreciate any help dealing with this issue
VTT at power up, from 0V to steady state
PGOOD PUed to 1.8V rail. Rises up at VTT's lowest point
Thank You