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TPS61088: The output of TPS61088 drifts with temperature, and the peak-to-peak value is over 50mV.

qing fang
Prodigy 40 points
Part Number: TPS61088

Tool/software:

We use TPS61088 to complete the 5V to 7V function.

We have tested 3 samples in temperature cycle test. One sample's output voltage changed greatly with temperature, and the peak-to-peak value exceeding 50mV. Is this normal?

The load current of VDD_7V is about 150mA, which is always in light load mode.

Circuit:

Test condition:

Temperature extremes: -5℃ to 50 ℃

Ramp rate: 2℃/minute(minimum) to 20℃/minute(maximum)

Dwell time: 60 minutes (at both extremes)

Total number of cycles to be run: 10

Test result:

Hope to get a reply as soon as possible. Thanks

  • 0
    TI__Genius 12205 points

    Hi Fang,

    Thanks for using E2E.

    We are not completely sure what happens for the large ripple unit one, but 50mV looks like is a value of the output voltage gap between light load and heavy load, 1.007*7V=49mV. So maybe there are some fluctuations on the load current so that the device operates between DCM and CCM, as a results the output voltage transition between the voltage in light load and in heavy load. 

    If that is the cause, it is a normal behavior for TPS61088.

    But it is hard to say more by now. We need to check these things:

    1. the part number of output capacitor C59 & C60 (or at least the package size and voltage rating if part number is not acceptable), we would like to check if it is within the recommended value in datasheet. 

    2.Does the abnormal one still have larger ripple over 50mV after the thermal test? Or it become normal after the test? If the large ripple still exists, can you please share the some waveforms like VOUT, SW, VIN? This would be helpful to know more about what happens for this unit and analyze the potential cause of the large ripple.

    Thanks.

    Regards,

    Nathan