Surge Stopper with Fault Latchoff

The LT4356-3 surge stopper protects loads from high voltage transients. It regulates the output during an overvoltage event, such as load dump in automobiles, by controlling the gate of an external N-channel MOSFET. The output is limited to a safe value thereby allowing the loads to continue functioning. The LT4356-3 also monitors the voltage drop between the VCC and SNS pins to protect against overcurrent faults. An internal amplifier limits the current sense voltage to 50mV. In either fault condition, a timer is started inversely proportional to MOSFET stress. If the timer expires, the FLT pin pulls low to warn of an impending power down. If the condition persists, the MOSFET is turned off, until the SHDN pin pulls low momentarily.

The auxiliary amplifier may be used as a voltage detection comparator or as a linear regulator controller driving an external PNP pass transistor.

Back-to-back FETs can be used in lieu of a Schottky diode for reverse input protection, reducing voltage drop and power loss. The SHDN input turns off the part, including the auxiliary amplifier, and reduces the quiescent current to less than 7µA.

LT4356-1

LT4356MP-1

LT4356-2

LT4356MP-2

LT4356-3

LT4356MP-3

Low Current Shutdown

7µa

60µa

7µa

Aux Amp In Shutdown

OFF

Always Alive

OFF

Fault Retry

Retry

Retry

Latchoff

Packages

DFN-12, MS-10, SO-16

DFN-12, SO-16

DFN-12, MS-10, SO-16

Temp Grades

C, I, H, MP

C, I, H, MP

C, I, H, MP

Applications

* Automotive/Avionic Surge Protection

* Hot Swap/Live Insertion

* High Side Switch for Battery Powered Systems

* Stops High Voltage Surges

* Adjustable Output Clamp Voltage

* Overcurrent Protection

* Wide Operation Range: 4V to 80V

* Reverse Input Protection to –60V

* Low 7µA Shutdown Current

* Adjustable Latchoff Fault Timer