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TPS7A47: Reverse current protection schottky spec

K. Sasaki14
Guru 10200 points
Part Number: TPS7A47

I think TPS7A4701 require reverse current protection schottky diode if Vout voltage level becomes higher than Vin.

In this case, I would like to know required diode spec.

Is forward current spec over 1A is better because TPS7A47 rated current is 1A?

How should we select schottky diode?

Best Regards,
Kohei Sasaki

  • 0
    TI__Genius 10490 points

    Hi Kohei Sasaki,

    Schottky diode protection is recommended for LDOs with pass transistors capable of conducting current in the reverse (OUT to IN) direction due to a body diode or parasitic diode. Since the TPS7A47 does not have a reverse diode between OUT and IN, it does not require reverse current protection.

    For future reference, instead of choosing based on the forward current rating, a Schottky diode should be selected from the I-V characteristic provided in the datasheet. The diode should have a forward voltage of 0.3 V when conducting 10 mA to 100 mA. This ensures that the Vout is clamped to Vin + 0.3 V, which prevents any parasitic or body diode between OUT and IN from turning on.

    Thanks,

    Gerard

  • 0 in reply to Gerard Copeland
    Guru 10200 points
    Gerard-san,

    Thank you for your reply.
    I checked another post about TPS7A47. So it has been described about reverse protection diode.
    e2e.ti.com/.../2615957

    Isn't reverse current protection diode require?

    Best Regards,
    Kohei Sasaki
  • 0 in reply to K. Sasaki14
    TI__Genius 10490 points
    Hi Kohei-san,

    Yes, the post you linked is correct. I apologize for my mistake and any confusion it may have caused. The TPS7A47 does require reverse current protection if the output voltage could exceed the input voltage by more than 0.3 V in your application. The Schottky diode should be chosen based on the I-V characteristics as explained in my previous response.

    Thanks,
    Gerard