MAX6495_09 Datasheet, PDF (1/16 Pages) Maxim Integrated Products – 72V, Overvoltage-Protection Switches/Limiter Controllers with an External MOSFET

19-3778; Rev 7; 8/09
EVAALVUAAILTAIOBNLEKIT
72V, Overvoltage-Protection Switches/
Limiter Controllers with an External MOSFET
General Description
The MAX6495–MAX6499 is a family of small, low-cur-
rent, 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 dur-
ing load-dump conditions, and the p-channel MOSFET
is off during reverse-battery conditions.
The MAX6497/MAX6498 feature an open-drain, undedi-
cated 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 V_OVSET 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.
Applications
Automotive
Industrial
Telecom/Servers/Networking
FireWire^®
Notebook Computers
FireWire is a registered trademark of Apple Computer, Inc.
Features
o Wide Supply Voltage Range: +5.5V to +72V
o Overvoltage-Protection Switch Controller Allows
User to Size External n-Channel MOSFETs
o Fast Gate Shutoff During Overvoltage with 100mA
Sink Capability
o Internal Charge-Pump Circuit Ensures 10V
Gate-to-Source Enhancement for Low R_DS(ON)
Performance
o n-Channel MOSFET Latches Off After an
Overvoltage Condition (MAX6497/MAX6499)
o Adjustable Overvoltage Threshold
o Thermal Shutdown Protection
o Supports Series p-Channel MOSFET for Reverse-
Battery Voltage Protection (MAX6496)
o POK Indicator (MAX6497/MAX6498)
o Adjustable Undervoltage Threshold (MAX6499)
o -40°C to +125°C Operating Temperature Range
o Small, 3mm x 3mm TDFN Package
Ordering Information
PART
PIN-PACKAGE
TOP MARK
MAX6495ATT+T
6 TDFN-EP*
AJM
MAX6495ATT/V+T 6 TDFN-EP*
AUG
Ordering Information continued at end of data sheet.
Note: All devices are specified over the -40°C to +125°C operating
temperature range.
+Denotes a lead(Pb)-free/RoHS-compliant package.
T = Tape and reel.
*EP = Exposed pad.
/V denotes an automotive qualified part.
Selector Guide appears at end of data sheet.
Pin Configurations
TOP VIEW
OUTFB GATE GND
6
5
4
MAX6495
1
2
3
IN SHDN OVSET
3mm x 3mm TDFN
Pin Configurations continued at end of data sheet.
________________________________________________________________ Maxim Integrated Products 1
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or visit Maxim’s website at www.maxim-ic.com.