1.2A Overvoltage/Overcurrent Protector

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. A PWRGD pin provides power good monitoring for VIN. The LTC4362 features a soft-shutdown controlled by the ON pin 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.

Applications

* USB Protection

* Handheld Computers

* Cell/Smart Phones

* MP3/MP4 Players

* Digital Cameras

* 2.5V to 5.5V Operation

* Overvoltage Protection Up to 28V

* Internal 40mΩ N-Channel MOSFET and 31mΩ RSENSE

* Avalanche Rated MOSFET Requires No Input Capacitor or TVS for Most Applications

* <1μs Overvoltage Turn-Off, Gentle Shutdown

* 2% Accurate 5.8V Overvoltage Threshold

* 20% Accurate 1.5A Overcurrent Threshold