Analog Devices

The LTC4361 overvoltage/overcurrent protection controller safeguards 2.5V to 5.5V systems from input supply overvoltage. It is designed for portable devices with multiple power supply options including wall adaptors, car battery adaptors and USB ports.The LTC4361 controls an external N-channel MOSFET in series with the input power supply. During overvoltage transients, the LTC4361 turns off the MOSFET within 1μs, isolating downstream components from the input supply. Inductive cable transients are absorbed by the MOSFET and load capacitance. In most applications, the LTC4361 provides protection from transients up to 80V without requiring transient voltage suppressors or other external components.The LTC4361 has a delayed start-up and adjustable dV/dt ramp-up for inrush current limiting. APWRGDpin provides power good monitoring for VIN. The LTC4361 features a soft shutdown controlled by theONpin and drives an optional external P-channel MOSFET for negative voltage protection. Following an overvoltage condition, the LTC4361 automatically restarts with a start-up delay. After an overcurrent fault, the LTC4361-1 remains off while the LTC4361-2 automatically restarts after a 130ms start-up delay.ApplicationsUSB ProtectionHandheld ComputersCell/Smart PhonesMP3/MP4 PlayersDigital Cameras

The LTC4362 monolithic overvoltage/overcurrent protector safeguards 2.5V to 5.5V systems from power supply overvoltage. It is designed for portable devices with multiple power supply options including wall adaptors, car battery adaptors and USB ports.The LTC4362 controls an internal 40mΩ N-channel MOSFET in series with the input power supply. During overvoltage transients, the LTC4362 turns off the MOSFET within 1μs, isolating downstream components from the input supply. In most applications, the LTC4362 rides through inductive cable transients without requiring transient voltage suppressors or other external components. An internal current sense resistor is used to implement overcurrent protection.The LTC4362 has a delayed start-up at plug-in and controlled dV/dt ramp-up for inrush current limiting. APWRGDpin provides power good monitoring for VIN. The LTC4362 features a soft-shutdown controlled by theONpin and drives an optional external P-channel MOSFET for negative voltage protection. Following an overvoltage condition, the LTC4362 automatically restarts with a 130ms delay. After an overcurrent fault, the LTC4362-1 remains off while the LTC4362-2 automatically restarts after a 130ms delay.ApplicationsUSB ProtectionHandheld ComputersCell/Smart PhonesMP3/MP4 PlayersDigital Cameras

The LTC4364 surge stopper with ideal diode controller protects loads from high voltage transients. It limits and regulates the output during an overvoltage event, such as load dump in automobiles, by controlling the voltage drop across an external N-channel MOSFET pass device. The LTC4364 also includes a timed, current limited circuit breaker. In a fault condition, an adjustable fault timer must expire before the pass device is turned off. The LTC4364-1 latches off the pass device while the LTC4364-2 automatically restarts after a delay. The LTC4364 precisely monitors the input supply for overvoltage (OV) and undervoltage (UV) conditions. The external MOSFET is held off in undervoltage and auto-retry is disabled in overvoltage.An integrated ideal diode controller drives a second MOSFET to replace a Schottky diode for reverse input protection and output voltage holdup. The LTC4364 controls the forward voltage drop across the MOSFET and minimizes reverse current transients upon power source failure, brownout or input short.APPLICATIONSAutomotive/Avionic Surge ProtectionHot Swap/Live InsertionRedundant Supply ORingOutput Port Protection

The LTC4365 protects applications where power supply input voltages may be too high, too low or even negative. It does this by controlling the gate voltages of a pair of external N-channel MOSFETs to ensure that the output stays within a safe operating range.The LTC4365 can withstand voltages between –40V and 60V and has an operating range of 2.5V to 34V, while consuming only 125μA in normal operation.Two comparator inputs allow configuration of the overvoltage (OV) and undervoltage (UV) set points using an external resistive divider. A shutdown pin provides external control for enabling and disabling the MOSFETs as well as placing the device in a low current shutdown state. A fault output provides status of the gate pin pulling low. A fault is indicated when the part is in shutdown or the input voltage is outside the UV and OV set points.The LTC4365 has a 36ms turn-on delay that debounces live connections and blocks 50Hz to 60Hz AC power. For fast recovery after faults, the LTC4365-1 has a reduced 1ms turn-on delay.ApplicationsPortableInstrumentationIndustrialAutomationLaptopsAutomotiveSurge Protection

The LTC4366 surge stopper protects loads from high voltage transients. By controlling the gate of an external N-channel MOSFET, the LTC4366 regulates the output during an overvoltage transient. The load may remain operational while the overvoltage is dropped across the MOSFET. Placing a resistor in the return line isolates the LTC4366 and allows it to float up with the supply; therefore, the upper limit on the output voltage depends only on the availability of high valued resistors and MOSFET ratings.An adjustable overvoltage timer prevents MOSFET damage during the surge while an additional 9-second timer provides for MOSFET cool down. A shutdown pin reduces the quiescent current to less than 14μA during shutdown. After a fault the LTC4366-1 latches off while the LTC4366-2 will auto-retry.ApplicationsIndustrial, Automotive and Avionic Surge ProtectionHigh Voltage DC Distribution28V Vehicle Systems

The LTC4367 protects applications where power supply input voltages may be too high, too low or even negative. It does this by controlling the gate voltages of a pair of external N-channel MOSFETs to ensure that the output stays within a safe operating range.The LTC4367 withstands voltages between –40V and 100V and has an operating range of 2.5V to 60V, while consuming only 70μA in normal operation.Two comparator inputs allow configuration of the overvoltage (OV) and undervoltage (UV) set points using an external resistive divider. A shutdown pin provides external control for enabling and disabling the MOSFETs as well as placing the device in a low current shutdown state. A fault output indicates that the GATE pin is pulling low when the part is in shutdown or the input voltage is outside the UV and OV set points.The LTC4367 has a 32ms turn-on delay that debounces live connections and blocks 50Hz to 60Hz AC power. For fast recovery after faults, the LTC4367-1 has a reduced turn-on delay of 500μs.ApplicationsPortable InstrumentationIndustrial AutomationAutomotive Surge (Load Dump) ProtectionNetwork Equipment

The LTC4368 protects applications from power supply voltages that may be too high, too low, or even negative and from overcurrent faults in both forward and reverse directions. The LTC4368 controls the gate voltage of a pair of external N-channel MOSFETs to ensure that the load is connected to the input supply only when there are no voltage or current faults.Two comparator inputs allow configuration of the overvoltage (OV) and undervoltage (UV) set points using an external resistive divider. A current sense resistor sets the forward and reverse circuit breaker current thresholds. After a forward current fault, the LTC4368 will either latchoff power, or retry after a user adjustable delay. After a reverse current fault, the LTC4368 waits for the output to fall 100mV below the input to reconnect power to the load.The LTC4368 has a 32ms turn-on delay that debounces live supply input connections and blocks 50Hz and 60Hz AC power. UV/OV faults also trigger the 32ms recovery delay before the external MOSFETs are turned back on.APPLICATIONSReverse Battery ProtectionPortable InstrumentationAutomotive and Industrial Surge ProtectionEnergy Storage Systems

The LTC4371 is a two-input negative voltage ideal diode-OR controller that drives external N-channel MOSFETs as a low dissipation alternative to Schottky diodes in high power –48V systems. Low power dissipation and voltage loss eliminates the need for heatsinks and reduces PC board area. Power sources can be easily ORed together to increase total system power and reliability.The LTC4371 tolerates ±300V transients such as those experienced during lightning-induced surges and input supply short-circuit events. The internal shunt regulator and low 350μA quiescent current allow the use of a large value dropping resistor to protect the supply pin against high voltage transients, while the high impedance drain pins can be similarly protected by high value series resistors without compromising diode operation.The 220ns reverse current turn-off is achieved by a powerful 2A gate driver with low propagation delay, thereby minimizing peak reverse current under catastrophic fault conditions. Open MOSFET and fuse faults are indicated at the FAULTB pin, which is capable of sinking 5mA to drive an LED or opto isolator.Applications–48V Telecom PowerAdvancedTCA SystemsNetwork Routers and SwitchesComputer Systems and Servers

The LTC4372/LTC4373are positive high voltage ideal diode controllers that drive an external N-channel MOSFET to replace a Schottky diode. They control the forward voltage drop across the MOSFET to ensure current delivery or current transfer from one path to the other even at light loads.A 5μA operating current achieves high efficiency for intermittent load applications or always-on backup power supplies. If a power source fails or is shorted, a fast turn-off minimizes reverse current transients. The LTC4372/LTC4373 control back-to-back N-channel MOSFETs for inrush current control and load switching.The LTC4372’s SHDN pin keeps the MOSFET off and reduces the quiescent current to 3.5μA. The LTC4373 has a UV pin for undervoltage monitoring while theUVOUTpin provides hysteresis adjustment and status information. During undervoltage, the back-to-back MOSFETs are cut off and quiescent current reduces to 0.5μA.APPLICATIONSAutomotive Battery ProtectionRedundant Power SuppliesPortable InstrumentationSolar Powered SystemsEnergy Harvesting ApplicationsSupply Holdup