MAX5968 Circuit-Breaker and Ideal Diode Controller with Digital Monitoring Functions

Product Details

The MAX5968 soft-switch and ideal diode controller protects systems with redundant DC-DC converter modules against failure of the converter by controlling external n-channel MOSFETs at the input and output of the converter. Input short-circuit and overload current protection is provided by means of a current-sense amplifier connected to a sense resistor that resides at the source of the external protection MOSFET. If a failure occurs at the input of the associated converter, the MAX5968 protects the input supply by pulling the gate of the input protection MOSFET low and disconnecting the failed converter. Similarly, if there is a failure at the output of the redundant converter, the MAX5968 detects the reverse potential across the output MOSFET and pulls the gate low to disconnect the failed converter from the load. The MAX5968 features VariableSpeed/BiLevel™ input circuit-breaker protection.

The MAX5968 also integrates a 10-bit ADC that monitors converter input current, load voltage, and output MOSFET forward voltage. An analog input (ADCIN) is provided to monitor a temperature signal from the associated converter. The MAX5968 features two 10-bit circular buffers that contain a history of the 50 most recent input current and output load voltage digital conversion results. This data helps to diagnose and troubleshoot converter failures. All ADC results, including circular buffers and several configuration registers are accessible through a 400kHz I²C interface.

Digital limits for overvoltage and undervoltage warning are user programmable. An active-low ALERT output notifies the system controller of any failure condition that arises or requires attention. When any of the measured signals violates digitally programmable limits, the active-low ALERT output is asserted.

A precision ON comparator input can be used to implement programmable undervoltage lockout for the input and output MOSFET drivers.

An open-drain active-low READY output can be used to enable the associated DC-DC converter by releasing the converter’s enable input when both the input and output MOSFETs are fully enhanced.

Two general-purpose I/Os can be fully configured through the I²C interface to provide external indications or to control additional peripheral devices.

The MAX5968 is available in a 28-pin thin QFN package and operates over the -40°C to +125°C temperature range.


  • High-Reliability Systems
  • Redundant DC-DC Converter Protection
  • Servers

Features and Benefits

  • 10-Bit ADC for Temperature, Voltage, Output MOSFET Forward Voltage, and Input Current Monitoring
  • Circular Buffers Store 50 Most Recent Voltage and Current Values for Fault Transient Analysis
  • Input Circuit-Breaker Controller Drives External Low-Side n-Channel MOSFET
  • Output Reverse-Current Protection Controller Drives Parallel External n-Channel MOSFETs
  • Programmable VariableSpeed/BiLevel Fault Protection Provides Electronic Circuit-Breaker Function
  • Internal 4A Pulldown Current for Fast Shutdown of the Circuit Breaker
  • Internal 600mΩ Gate Drive for Fast On-Off Control of the ORing FETs
  • Minimum- and Maximum-Value Detection Registers for All Digitized Signals
  • Two GPIO Pins
  • 400kHz I²C Interface
  • Small, 5mm × 5mm, 28-Pin TQFN Package