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scott239955_stm1_stmicro_com
Associate II
Apr 29, 2021 5:31 PM UTC
Question

STUSB4500: VBUS_EN_SNK seems redundant in certain applications.

We are using the STUSB4500 and we plan to use VBUS_EN_SNK in its default mode. This means that the whenever a source is attached, that power is passed on downstream. That begs the question: what's the point of using VBUS_EN_SNK and the FET it controls? Why not just connect incoming power to the downstream circuits permanently?

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    2 replies

    Winfred LU
    ST Employee
    May 4, 2021 5:05 AM UTC

    That FET is to ensure the cold socket, preventing incoming negative voltage on VBUS.

    Depending on your application needs, it is OK to remove the FET (to save cost or PCB space) but it will not be protected for negative voltage nor reverse battery.

    scott239955_stm1_stmicro_com
    Associate II
    May 4, 2021 5:25 AM UTC
    That’s helpful — thank you!
    Scott