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TPS65219: abnormal output

Moon Wang
Intellectual 1285 points
Part Number: TPS65219


Tool/software:

Hi Expert,

My customer use TPS6521907RHBR to power AM6254ATCGGAALW. They tested Vsys =5V, Vpin14(C283)=1.8V, which are normal. But there is no Vout from other output pin. Below is the schematic, could you please help find the root? What should they test next step?

BR,

Moon

  • 0
    TI__Expert 6075 points

    Hi Moon,

    07 version of this device has MODE/STBY pin configured as Mode and STABY, this pin needs to be pulled high for normal operation, can you please check with customer if the pin is high?

    Sathish

  • 0 in reply to Sathish Vallamkonda
    TI__Intellectual 1285 points

    Hi Sathish,

    Thanks for your reply!  According to your advice, my customer changed their design of MODE/STBY pin with a 6.8k pullup resistor as below:

    VSYS=5V, The waveform of VSYS and MODE/STBY is in below pic:

    The other output pin waveforms are:

    But in BUCK2, there is still no output. Could you help check the issue?

    BR,

    Moon

  • 0 in reply to Moon Wang
    TI__Expert 6075 points

    Hi Moon,

    Thank you for the waveforms.

    As you can see Buck2 output is set to 3.3V but it can only go up to ~1.8V and as it comes up there is a disturbance on VSYS.

    On the schematic Buck2 output (LX_B2) is also labeled as SW_VCC_1P8. Can you please ask the customer where is it connected? Similarly it is done for the remaining Bucks. The LX side of the inductor should not be connected to anything.

    Sathish