General Description
The MAX6495–MAX6499 is a family of small, low-current, overvoltage-protection circuits for high-voltage transient systems such as those found in automotive and industrial applications. These devices monitor the input voltage and control an external n-channel MOSFET switch to isolate the load at the output during an input overvoltage condition. The MAX6495–MAX6499 operate over a wide supply voltage range from +5.5V to +72V.
The gate of the n-channel MOSFET is driven high while the monitored input is below the user-adjustable over voltage threshold. An integrated charge-pump circuit provides a 10V gate-to-source voltage to fully enhance the n-channel MOSFET. When the input voltage exceeds the user-adjusted overvoltage threshold, the gate of the MOSFET is quickly pulled low, disconnect ing the load from the input. In some applications, dis connecting the output from the load is not desirable. In these cases, the protection circuit can be configured to act as a voltage limiter where the GATE output saw tooths to limit the voltage to the load (MAX6495/MAX6496/MAX6499).
The MAX6496 supports lower input voltages and reduces power loss by replacing the external reverse battery diode with an external series p-channel MOSFET. The MAX6496 generates the proper bias voltage to ensure that the p-channel MOSFET is on during normal operations. The gate-to-source voltage is clamped during load-dump conditions, and the p-channel MOSFET is off during reverse-battery conditions.
The MAX6497/MAX6498 feature an open-drain, undedicated comparator that notifies the system if the output falls below the programmed threshold. The MAX6497 keeps the MOSFET switch latched off until either the input power or the SHDN pin is cycled. The MAX6498 will autoretry when VOVSET falls below 130mV.
These devices are available in small, thermally enhanced, 6-pin and 8-pin TDFN packages and are fully specified from -40°C to +125°C.

FEATUREs
♦ Wide Supply Voltage Range: +5.5V to +72V
♦ Overvoltage-Protection Switch Controller Allows
   User to Size External n-Channel MOSFETs
♦ Fast Gate Shutoff During Overvoltage with 100mA
   Sink Capability
♦ Internal Charge-Pump Circuit Ensures 10V
   Gate-to-Source Enhancement for Low RDS(ON)
   Performance
♦ n-Channel MOSFET Latches Off After an
   Overvoltage Condition (MAX6497/MAX6499)
♦ Adjustable Overvoltage Threshold
♦ Thermal Shutdown Protection
♦ Supports Series p-Channel MOSFET for Reverse
   Battery Voltage Protection (MAX6496)
♦ POK Indicator (MAX6497/MAX6498)
♦ Adjustable Undervoltage Threshold (MAX6499)
♦ -40°C to +125°C Operating Temperature Range
♦ Small, 3mm x 3mm TDFN Package

APPLICATIONs
   Automotive
   Industrial
   Telecom/Servers/Networking
   FireWire®
   Notebook Computers