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TPS610986: MODE LOW,VSUB?

Part Number: TPS610986
Other Parts Discussed in Thread: TPS61098

hi:

TPS610986, input 1.5V, output 3.3V, VSUB is followed by a load of 3-5mA,

MODE is low, some VSUBs have charging and discharging waveforms, and some have high levels.

How to understand this.

  • Hi Kevin,

    I think it may not an expected behavior of TPS61098.

    There are several things I want to check,

    what is connected with MODE pin? Is it a MCU IO pin or some other things? 

    Is there any load on VMAIN?  Is VMAIN a stable 3.3V?

     Regards,

    Nathan

  • hi:

     1. what is connected with MODE pin? Is it a MCU IO pin or some other things? 

       MCU IO.

      2.Is there any load on VMAIN?  

      yes

    3.Is VMAIN a stable 3.3V?

     yes

  • Hi Kevin,

    So what the load current from VMAIN?

    And more, in condition 2 and condition 3, MODE are both logic low level, but the VSUB conditions are different, what the setup differences between this two conditions?

    Nathan

  • hi Nathan:

     1. So what the load current from VMAIN?  

        normal:  50 mA,   standby:60 uA.

    2.And more, in condition 2 and condition 3, MODE are both logic low level, but the VSUB conditions are different,

        what the setup differences between this two conditions?

         The difference is that customers want to know why?

  • Hi kevin,

    Ok, I knew, sorry that I got something wrong about your question before.

    So does this mean that customer tried several chips and some chips get high level but some chips don't get, or that customer only tried one chip and sometimes get high level but don't get high level other times?

    some VSUBs have charging and discharging waveforms, and some have high levels.

    Regards,

    Nathan

  • hi Nathan:

    total 6000 PCS,MODE PIN LOW,  57% VSUB PIN    LOW or charging and discharging waveforms,   43%   VSUB PIN HIGH.

  • Hi Kevin, 

    Does customer check that the mode pin voltage < 0.4V? Maybe the logic low voltage level not exactly equal to 0 due to noise.

    Nathan

  • Hello Kevin,

    As we did not hear back from you, I expect the issue is solved and I will close this thread. If you have further questions, please post below or start a new thread.

    Best regards,
    Brigitte