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TPS65910: the wrong voltage

desheng LI
Intellectual 545 points
Part Number: TPS65910

hi！The schematics design is like the  AM335x starterkit's

when the IC is powered on, the voltage  measured on this board:
VRTC=2.5
VCC1=5
VCC2=5
VCC3=5
VCCIO=5
VDIG1=5V
VDIG2=3.3
VAUX33=3.3

VAUX1=0.9

VAUX2=2.36

VMMC=3.8

VREF=0.85V

  • 0
    TI__Mastermind 30260 points

    Referring to this document:

    TPS65910Ax User's Guide for AM335x Processors

    The following voltages should be present on the LDO output rails:

    • VDIG1 = 1.8V
    • VDIG2 = 1.8V
    • VAUX1 = 1.8V
    • VAUX2 = 3.3V
    • VAUX33 = 3.3V
    • VMMC = 3.3V
    • VPLL = 1.8V
    • VDAC = 1.8V

    And the TPS65910 datasheet shows:

    • VRTC = 1.8V
    • VREF = 0.85V

    Please refer to the TPS65910 Schematic Checklist and see if there are any issues with the wiring of the TPS65910 that need to be addressed.

    It is concerning that only one of your LDO outputs is producing the correct voltage. The internal bandgap voltage (VREF) is correct, but none of the other voltages are correct except for VAUX33.

    You are using the TPS65910A3 version, which turns on VRTC in low-power mode. Have you tried using the TPS65910A31 version, which turns on VRTC in high-power mode? This is the only debug method I can recommend at this time.

  • 0 in reply to Brian Berner
    Intellectual 545 points

    I

    The schematics design is in  the pic.its different with the   the  AM335x starterkit's，and I'm using the TPS65910AA1RSL now。

    Parallel a 1K resistor on the capacitor of vrtc as the dummy load, the voltage changes to 1.8V, but other voltages are 0V。

  • 0 in reply to desheng LI
    TI__Mastermind 33320 points

    Hi, ,

       Would you please let's know how many boards have the issue? It may be a cold soldering issue; I mean it looks like the device is not soldered properly.