LTC7862 Datasheet

The LTC7862 high efficiency switching surge stopper protects loads from high voltage transients. High efficiency switching allows high output currents, small solution sizes, and high reliability. During an input overvoltage event, the LTC7862 controls the gates of two external N-channel MOSFETs to act as a switching DC/DC step-down regulator. This maintains the output voltage at a safe value, allowing the loads to continue to operate through the input overvoltage event. During normal operation, the LTC7862 turns on the top external N-channel MOSFET continuously, passing the input voltage through to the output, with minimal voltage drop. Using a fast peak current comparator, the LTC7862 also limits the maximum output current to protect against overcurrent and short-circuit faults.

An adjustable timer limits the time that the LTC7862 can spend switching during an overvoltage, overcurrent, or startup condition. When the timer expires, the external MOSFETs are turned off for a cooldown period and then the LTC7862 restarts. By strictly limiting how long the LTC7862 can switch, when the power loss is relatively high, the components and thermal design can be optimized for normal pass-through operation while still safely operating through high voltage input surges and/or overcurrent events.