The NCP391 is able to disconnect the systems from its output pin in case wrong input operating conditions are detected.The system is positive overvoltage protected up to +28 V.
Due to this device using internal NMOS, no external device is necesary, reducing the system cost and the PCB area of the application board.
The NCP391 is able to instantaneously disconnect the output from the input, due to integrated Low R
Power NMOS (120 mΩ, if the input voltage exceeds the overvoltage threshold (OVLO) or undervoltage threshold (UVLO)).
At powerup (EN(BAR) pin = low level), the V
turns on ton after the V
exceeds the undervoltage threshold.
The NCP391 provides a negative going flag(FLAG(BAR)) output, which alerts the system that a fault has occurred.
In addition, the device has ESD-protected input (15 kV Air) when bypassed with a 1.0 µF or larger capacitor.

• Overvoltage Protection up to 28 V
• On-Chip Low R
• NMOS Transistor: 120 mΩ
• Overvoltage Lockout (OVLO)
• Undervoltage Lockout (UVLO)
• Internal Soft start
• Alert FLAG(BAR) Output
• Shutdown EN(BAR) Input
• ESD Ratings:Machine Model = B, Human Body Model = 3