Hi team,
My customer designed TL431 (U5501 on the attachment) is designed in our project as the reference voltage for the MCU. Some issue was found on the fail boards (FA units from our customer) and the issue may be caused by the oscillation on MCU_VREF_2V7. There is the 10uF caps (C5513) on the output site of TL431. Please help to have the comment why there is the oscillation on the output site. Have no idea if you are right person to this issue.
Please advise the possible root cause and what's next step to do?
I attached portion circuit and their testing waveforms for reference. You can see there is oscillation symptom in 2.7V ref. voltage.
Thanks
