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Original question:

TPS7A8300: About out put cap

TPS7A8300: large output capacitor

Hans
Genius 12865 points
Part Number: TPS7A8300

Hello Team,

can the output capacitor be >1mF without impacting the stability, please? According the data sheet there is no limit.

Thanks and Best Regards,

Hans

  • 0
    TI__Mastermind 23361 points
    Hi Hans,

    TPS7A8300 datasheet does not specify any limit for the high side of the capacitors. However here are the things you may need to consider to have a 1mF capacitor at output.

    1. During startup, the output cap may require a large current to charge it for an extended amount of time that may put the device into current limit. The current limit may put the parts into thermal shutdown.

    2. The datasheet recommends to have ceramic capacitor with low ESR. 1mF capacitor may have higher ESR and it may have stability issue with the control loop. If customer needs to have the big capacitor there, I would suggest to have a smaller capacitor in uF range and put it in parallel with the big cap and this will help to lower the ESR.

    3. With such a cap at output, there is risk for reverse current event. When the supply of the LDO drops, the output may take a longer time to be discharged and during this time, the voltage differential between output and input of the LDO may turn on the body diode of the LDO and it may cause damage. The application may need external diodes to prevent this reverse current back into the output pin of the LDO.

    Regards,
    Jason Song