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TPS62873: Rdson of the MOSFET for power good pin

Shunsuke Yamamoto
Expert 8471 points
Part Number: TPS62873
Other Parts Discussed in Thread: TPS62871, TPSM82821A, TPSM82823A

Tool/software:

Hi team,

May I know the value of Rdson of the MOSFET for power good pin including variance in TPS62873, TPS62871, TPSM82821A and TPSM82823A?

Best regards,

Shunsuke Yamamoto

  • 0
    TI__Guru**** 151520 points

    Hi Yamamoto-san,

    Are they trying to calculate a pull-up resistor value, drive an LED, or something else?  This app note explains about the PG pin: https://www.ti.com/lit/an/slva485/slva485.pdf

    We only specify the maximum Rdson for these devices, which is calculated from V=IR.  The maximum value of the logic low voltage at the specified test current gives the maximum Rdson.

    Chris

  • 0 in reply to Chris Glaser
    TI__Expert 8471 points

    Hi Chris-san,

    Thank you for the reply. It is good to know that we define the pull-up resistor value based on the leakage current on PG pin and output voltage. I tried to calculate maximum value of pull-up resistor and minimum value of pull-up resistor of TPS62873, but I wasn't able to find some parameters such as leakage current. What parameter should I refer to in the datasheet? Is the parameter highlighted orange in the table below the leakage current or I_pull-up?

    Chris Glaser said:
    We only specify the maximum Rdson for these devices, which is calculated from V=IR.  The maximum value of the logic low voltage at the specified test current gives the maximum Rdson.

    Could you please kindly let me know more detailed? How much is the specified test current?

    Best regards,

    Shunsuke Yamamoto 

  • +1 in reply to Shunsuke Yamamoto
    TI__Guru**** 151520 points

    Yes, the 200nA is the leakage current.

    The Rdson is calculated from the VOL:

    At 1 mA, the PG FET gives 0.3V at most, so this is a maximum Rdson of 300 Ohm.

    Chris