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  • Resolved

TPS62065-Q1 power output unstable

Prodigy 205 points

Replies: 4

Views: 119

Part Number: TPS62065-Q1

Hi, 

My design information is below.

Device: TPS62065-Q1

Input voltage: 5V

Output voltage: 2V

Output current: about 500mA

Temperature: 25°C

Schematic as below attached.

When I measure the voltage of the FB pin, or lay a finger or any other conductor (such as the probe of oscilloscope) on this pin, it will work abnormally.

I have done some change such as change the mode to fix frenquency mode, add input and output cap, decrease the FB up and down res, but the issue is still as before.

I have test the PWM waveform when  fix frenquecy mode or power save mode, the PWM signal is not very stable.

Do you have some suggestion about it ?

Thanks!

  • Hi Lei,

    FB is the voltage feedback pin, it is a sensitive pin. you can test the SW pin and output to see if the device is stable without touching FB pin. Also, you can check if your device is well soldering and well layout.

    Best Regards,

    Kevin

    If this answers your question, Please click "This resolved my issue" button.
    ____________________________________________
    TPS62810-Q1 – New Automotive 6Vin, 2.25MHz buck family with 1% accuracy and SYNC-pin. 1-2-3-4A options.
    Smallest 2x3QFN package with wettable-flanks for optical PCB inspection

  • In reply to Kevin-Cheng:

    Hi, Kevin

    Yes, this pin is sensitive. But I need do some HW test  such as measure the voltage, so I think it should work well.

    And I have test the SW pin when configed as power save mode and fix switching frenquency mode, the PWM waveform seems not stable.

  • In reply to Lei:

    Hi Lei,

    Generally, this kind of test is not problematic, I can help you review the schematic and layout if you can send it to me. For external factors such as welding, test probe and test method, it may need to be ruled out by yourself. And you can send out the unstable PWM waveform, I can take a look to find the problem.

    Best Regards,

    Kevin

    If this answers your question, Please click "This resolved my issue" button.
    ____________________________________________
    TPS62810-Q1 – New Automotive 6Vin, 2.25MHz buck family with 1% accuracy and SYNC-pin. 1-2-3-4A options.
    Smallest 2x3QFN package with wettable-flanks for optical PCB inspection

  • In reply to Kevin-Cheng:

    Hi Lei,

    since I am communicating with you in other ways, I will close this item. Thanks.

    Best Regards,

    Kevin

    If this answers your question, Please click "This resolved my issue" button.
    ____________________________________________
    TPS62810-Q1 – New Automotive 6Vin, 2.25MHz buck family with 1% accuracy and SYNC-pin. 1-2-3-4A options.
    Smallest 2x3QFN package with wettable-flanks for optical PCB inspection.

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