• Locked Locked
  • Replies 2 replies
  • Subscribers 62 subscribers
  • Views 308 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TPS546A24A: Internal pull-up at EN/UVLO pin

teritama
Expert 1570 points
Other Parts Discussed in Thread: TPS546A24A, TPS62913
  • Part Number: TPS546A24A

Hi team,

In datasheet EN/UVLO pin has internal pull-up(Ihys) like below figure. We try to use this pull-up as pull-up of Power good pin on TPS62913.

But, TPS546A24A doesn't output voltage. 

Can we use this internal pullup? Or Does it need some setting to use this pull-up?

Best regards,

teritama

  • Expert 1570 points

    Hi team,

    I would appreciate it if you could give your response.

    If I should write more information, let me know.

    Best regards,

    teritama

  • TI__Mastermind 48180 points

     

    My deepest apologies for the delay in the response.  Due to a system error with our E2E forum, we did not see your post until now.

    Yes, the TPS546A24A has an internal pull-up current source on the Enable pin called "Ihys", but this current is disabled by the CNTRL signal when EN/UVLO is low.  That is why you are not seeing any voltage on the EN/UVLO pin when it is connected to the PGOOD pin of the TPS62913.  In fact, when the TPS546A24A is disabled (EN/UVLO < 0.9V) the EN/UVLO pin is loaded with a small pull-down resistance (100nA typical) to prevent the EN/UVLO pin from "drifting" on without an intentional external pullup.

    To enable the TPS546A24A with the PGOOD of the TPS62913, you will need an external pull-up capable of overcoming the 100nA leakage current of the TPS546A24A and the 500nA leakage current of the TPS62913 while still exceeding the 1.05V threshold of the TPS546A24A.