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Original question:

TPS7B63-Q1: Output terminal electrolytic capacitor capacity

TPS7B63-Q1: Output terminal electrolytic capacitor capacity

rui saito
Prodigy 240 points
Part Number: TPS7B63-Q1

Hello,team

We conduct tests using actual equipment to see if there is any problem with placing a capacitance greater than the value in the data sheet on the output terminal.
Could you please advise what aspects I should check when investigating whether the device is working as intended?

The points I'm currently thinking of checking are as follows.
・The output voltage must be within 4.9~5.1V before the MCU starts up.

Regards,
Saito

  • 0
    TI__Genius 15125 points

    Hello,

    Thank you for your question.

    By using a capacitor greater than the value specified in the datasheet, we cannot guarantee that our datasheet specifications will match exactly to what you may see on your end, especially in terms of graphs, i.e. line and load transients. Using a large cap can cause stability concerns with the LDO.

    This app note may explain more about stability concerns with a large output capacitor:

    AN-1482 LDO Regulator Stability Using Ceramic Output Capacitors (Rev. A) (ti.com)

    The cap will also take a long time to charge up, which may risk the device entering into thermal shutdown if this results in an increase in wattage across the LDO. 

    Best Regards,

    Hannah

  • 0 in reply to Hannah Grace
    Prodigy 240 points

    Hello,Hannah-san

    Thank you for your reply.

    I received an answer in the original question that changing the capacitor makes the LDO output unstable.

    On the other hand, I also received the answer, "I could try test if the device is functioning as you intended with the given capacitance.''
    So I was wondering about their perspective on the test.

    Is it okay to check the following two points based on the answers you received?
    ・Voltage stability
    ・IC wattage consumption

    Regards,
    Saito

  • 0 in reply to rui saito
    TI__Genius 15125 points

    Hello Saito-san,

    Yes, you could check voltage stability and power consumption on the device under your prospective conditions. Please keep in mind that what I have stated above should still stand true when you test a part. You will still see problems with stability at your output.

    Best Regards,

    Hannah