High-Voltage, Overvoltage/Undervoltage, Protection Switch Controller

Please check latest availability status for a specific part variant.


The MAX6399 is a small overvoltage and undervoltage protection circuit. The device can monitor a DC-DC output voltage and quickly disconnect the power source from the DC-DC input load when an overvoltage condition occurs. A power-OK output signals when the DC-DC input voltage falls below an adjustable threshold. This controller architecture provides the ability to size the external n-channel MOSFET to meet specific load current requirements.

When the DC-DC monitored output voltage is below the user-adjustable overvoltage threshold, the GATE output of the MAX6399 goes high to enhance the n-channel MOSFET. The MAX6399 offers internal charge-pump circuitry that allows the GATE voltage to be 10V above the input voltage (VGS = 10V) to fully enhance the external n-channel MOSFET, thus minimizing the drain-to- source resistance.

When the monitored output voltage rises above the user-adjusted overvoltage threshold, the GATE output rapidly pulls low to shut off the MOSFET. The MOSFET remains latched off until either the MAX6399 input power or SHDN-bar input is cycled. The MAX6399 includes a logic-low shutdown input that disables the GATE. An internal overtemperature detector also disables the gate when the MAX6399 temperature reaches the thermal-shutdown threshold.

The device operates over a wide supply voltage range (5.75V to 72V) and is offered in a small TDFN package, fully specified from -40°C to +125°C.

MAX6399: Typical Operating Circuit MAX6399: Typical Operating Circuit Enlarge+

Key Features

  • High-Voltage Capability (72V) Allows Direct Monitoring, Ensuring Reliable System Operation in Automotive and Industrial Applications
    • Wide Supply Voltage Range (5.75V to 72V)
    • Specified from -40°C to +125°C
    • Adjustable DC-DC Input Undervoltage-Threshold Power-OK Output
    • Adjustable DC-DC Output Overvoltage Thresholds
  • Integrated Protection Features Improve System Reliability
    • Internal Charge Pump Ensures n-Channel MOSFET is Fully Enhanced During Normal Operation (VGS = 10V)
    • Fast GATE Shutoff During Overvoltage with 20mA Sink Capability
    • Latches Off External n-Channel MOSFET During High-Voltage Transients
    • Overtemperature-Shutdown Protection


  • Networking
  • RAID
  • Server
  • Telecom

Pricing Notes:
This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific and version-specific prices and delivery, please see the price and availability page or contact an authorized distributor.
Product Reliability Reports: MAX6399.pdf 
Device   Fab Process   Technology   Sample size   Rejects   FIT at 25°C   FIT at 55°C   Material Composition  

Note : The failure rates are summarized by technology and mapped to the associated material part numbers. The failure rates are highly dependent on the number of units tested.

Quality Management System >
Environmental Management System >


Related Resources