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Extending protection for reverse polarity beyond -40V

Category: Hardware
Product Number: LTC4367

Dear all,

The limit on reverse polarity protection for this device to be -40V is well understood, so an alternative must be found if you're potentially powering from (say) a 48V supply.

Can I ask if a low drop diode in series with the ground connection for the device could be a suitable answer? I'm thinking low-drop Schottky could be used to ensure current flows the correct way through the device. It would apply a small offset to the shutdown and fault pins, but that should be manageable. The OV comparator could also be referenced to the same node. Is the gate guaranteed to be low in this condition?

Something like this:

Any thoughts?

Parents
  • Dear all,

    Here's the kind of thing I'm suggesting may work....has custom models in it so you'll likely need to make a replica using your own libraries. LTC4367_Minus48V.asc 

    I don't know enough about the LTC4367 model to know if it correctly simulates reverse battery behaviour - and of course, the simulation certainly won't tell you if you're going to damage the part or other hardware.

    Thanks and Regards, 

Reply
  • Dear all,

    Here's the kind of thing I'm suggesting may work....has custom models in it so you'll likely need to make a replica using your own libraries. LTC4367_Minus48V.asc 

    I don't know enough about the LTC4367 model to know if it correctly simulates reverse battery behaviour - and of course, the simulation certainly won't tell you if you're going to damage the part or other hardware.

    Thanks and Regards, 

Children
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