The LTC4360/LTC4361/LTC4362 overvoltage/overcurrent protection controllers safeguard 2.5V to 5.5V systems from input supply overvoltages and overcurrents. They are designed for portable devices with multiple power supply options including wall adapters, car battery adapters and USB ports. The LTC4360 controls an external N-channel MOSFET in series with the input power supply to provide up to 80V of transient protection. During overvoltage transients, it 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 LTC4360 provides protection from transients up to 80V without requiring transient voltage suppressors or other external components. The LTC4361 is similar to the LTC4360 but also includes overcurrent protection with the addition of an external sense resistor. The LTC4362 features an integrated MOSFET and sense resistor, which reduce external component count and simplify the design. It provides overvoltage protection up to 28V and overcurrent protection to 1.2A. Other features of this family include an adjustable dV/dt ramp-up for inrush current limiting, a PWRGD pin provides power good monitoring for VIN, a gentle shutdown and optional negative input voltage protection with the addition of an external P-FET.