• State
  • Locked Locked
  • Replies 2 replies
  • Subscribers 98 subscribers
  • Views 642 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

AM3352: AM335x power-up sequence with TPS650250

Kummi
Mastermind 6220 points
Part Number: AM3352
Other Parts Discussed in Thread: TPS650250

Hi,

Has anyone used TPS650250 with Clamping Circuit as described on the Application note(SLVU731A)?
That clamping ciruit is suggested for AM335x Simultaneous Ramp Down.

The power-down sequence is OK, but, there is an issue in power-up sequence with this Clamping Circuit.
During power up, after the 1.8V line is powered up, there is a short voltage(0.6V)
induced into the 3.3V before 3.3V line is powered up as shown below.


This issue is being discussed on the TPS650250 forum here and got the commnet below.

"If the rise in voltage on the 3.3V rail during the power-on sequence did not immediately cause a problem
in your system then I do not expect it to cause any problems in the future. If the sequence order is still
intact, then this minor deviation on the 3.3V rail will have no impact."

Please let me know if there is no issue with that initial 0.6V jump on 3.3V during power-up
with regards to AM335x.

Best Regards
Kummi

  • 0
    TI__Guru**** 161600 points
    Hi Kummi,

    In general the comment is correct. If the PMIC is wired as described in the datasheet, AM335x Schematic Checklist (processors.wiki.ti.com/.../AM335x_Schematic_Checklist) and the reference AM335x designs, then I don't expect to have any problems in the future.

    FYI, I did not see the relevant PMIC part of the schematic attached in the other forum post. Could you share it or can you confirm you've connected the TPS650250 according to the datasheet requirements? Which voltage rails are you monitoring?

    Best Regards,
    Yordan
  • 0 in reply to Yordan Kovachev
    Mastermind 6220 points
    Hello Yordan,

    Thank you for the quick reply.

    The PMIC part number is TPS650250RHBR and the schematics are as per the
    checklist/datasheet, it was reviewed by AM335x team.
    All the necessary voltage rails DCDC1/DCDC2/DCDC3/VLDO1-3 are measured
    and the power-up sequence is as per the manual, except that glitch on the 3.3V.

    Can we assume this is OK and there won't be any issue in long run?

    Best Regards
    Kummi