The LM73100 device is internally protected against transient and steady state negative voltages applied at the input supply pin. The device blocks the negative voltage from appearing at the output, thereby protecting the load circuits. There’s no reverse current flowing from output to the input in this condition. The maximum negative voltage the device can handle at the input is limited to -15 V or V_OUT – 21 V, whichever is higher. It’s also recommended that all signal pins (e.g. EN/UVLO, OVLO, PGTH) which are derived from input supply should have a sufficiently large pull-up resistor to limit the current flowing out of these pins during reverse polarity conditions. Please refer to Absolute Maximum Ratings table for more details.