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TPS54821: TPS54821 using problem

user5102208
Intellectual 820 points
Part Number: TPS54821

Dear all ,

There is something confusing about tps54821 using.The follow decription is found from it's datasheet:

The EN pin has an internal pull-up current source that can be used to adjust the input voltage
under voltage lockout (UVLO) with two external resistors. In addition, the EN pin can be floating for the device to
operate with the internal pull-up current.

1 how many is the internal pull-up current?

2 If the EN pin is controlled with the PG signal of the front stage power supply,can it be directly connected without the pull resistance????ou


Many thanks ! and looking forward to your reply!!!

  • 0
    TI__Genius 9550 points
    Hi,
    please find my input for your questions.
    1. for pull high current value, refer datasheet page 5-> 6.5 Electrical Characteristics/ENABLE AND UVLO (EN PIN)/input current 1.15uA; page 13 equation 3 description.
    2. Yes, you can use frond stage power supply PG to control EN without Pull high resister. one parameter need to check: check the leackage current of the PG pin when pull high (frond stage power supply). Suggest to leave the pull up resister place on Board.