Is the normal operating current also 50A? There are ways to protect against reverse polarity using a series MOSFET.crutschow, the details aren't necessarily proprietary but its just a small component of a larger system. It has to do with reverse polarity protection. I don't want to sway from the discussion but I'm doing reverse polarity protection for a maximum of 50 A at a system level. These flyback diodes on low-side drivers cause a lot of grief when it comes to this protection under some fault conditions.
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