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TPS2121: CP2 Floating implications

Steve Widener
Genius 9575 points
Part Number: TPS2121

What are the implications if the CP2 is left floating? Will the TPS2121 default to one state or the other or could there be instability?

  • +1
    TI__Mastermind 32650 points

    Hi Steve,

    We recommend that CP2 is grounded if it is not required. This is an control pin and so a floating node here could result in various operating states depending on the coupled voltage onto that pin. You can safely connect this pin to GND if it is not required.

    Thanks,

    Shreyas

  • 0 in reply to Shreyas Dmello
    Prodigy 65 points

    Hello Shreyas,

    All the future designs will have the CP2 pulled up. The schematic has provision for both the pull up or pull down. With the current design (CP2 floating), I am trying to understand if there are any corner case issues that might be problematic for the part. Also as a side note, we have a switching regulator output tied to IN1 and USB power on IN2 of TPS2121. How does CP2's floating condition affect these inputs and the output of TPS2121?

  • 0 in reply to Sushant Sharma
    TI__Mastermind 32650 points

    Hi Sushant,

    A floating input is undefined and therefore the behaviour is undefined. There could be a case where CP2 does not have any stray voltage on it and it goes to GND, but there is always the possibility that coupling from the system could cause the voltage on this pin to rise above V_ref. These are all possibilities since there is no internal pull down or pull up on this pin.

    As such, we do  not recommend leaving this pin in an undefined stage. Please ground it or pull it depending on the design needs.

    Thanks,

    Shreyas