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TPS25947: Reverse polarity protection for EN/UVLO, OVLO, and PGTH pins

Kaji@PAN
Mastermind 7785 points
Part Number: TPS25947

Tool/software:

Hello,

I have a question about reverse polarity protection for the EN/UVLO, OVLO, and PGTH terminals.
If the above signal terminals are connected to IN, there is a note in the data sheet about pull-up resistors.
However, the absolute maximum rating of these pins is MIN=-0.3V.
Does this IC have a protection circuit for the signal pins inside?
The data sheet does not explain how the signal pins are protected against reverse polarity voltage, so please let me know.

Best regards,

  • +1
    TI__Mastermind 38475 points

    Hi Kaji-san,

    Let me explain what happens when the negative voltage is applied to the device. There are ESD diodes at each pin from GND to pin direction. When the negative voltage is applied, these diodes conduct current but they are not designed for continuous current flow and can get damaged. When you have large resistors for pullup, they will limit the current to safe value when negative voltage is applied. For the IN pin, there is dedicated protection. The above mentioned abs min is indeed based on these ESD diodes rating. When the current is limited then this is fine. In general we don't want them to conduct current and if negative voltage below the diode drop (~0.3V) is applied, the current will flow hence the spec mentioned above.

    Best Regards,
    Arush