LT4356-3

1

Rev D

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APPLICATIONS

FEATURES

DESCRIPTION

Surge Stopper with

Fault Latchoff

The LT®4356-3 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

against overcurrent faults. An internal amplifier limits

the current sense voltage to 50mV. In either fault condi-

tion, 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.

n

Automotive/Avionic Surge Protection

n

Hot Swap/Live Insertion

n

High Side Switch for Battery Powered Systems

n

Stops High Voltage Surges

n

Adjustable Output Clamp Voltage

n

Overcurrent Protection

n

Wide Operation Range: 4V to 80V

n

Reverse Input Protection to –60V

n

Low 7µA Shutdown Current

n

Adjustable Latchoff Fault Timer

n

Controls N-channel MOSFET

n

Shutdown Pin Withstands –60V to 100V

n

Fault Output Indication

n

Auxiliary Amplifier for Level Detection Comparator or

Linear Regulator Controller

n

Available in 12-Pin 4mm × 3mm DFN,

10-Pin MSOP, and 16-Pin SO Packages

4A, 12V Overvoltage Output Regulator

Overvoltage Protector Regulates Output at

27V During Transient

0.1µF

10

10m

IRLR2908

12V

43563 TA01

LT4356DE-3

GND

TMR

OUT

GATE

SNS

SHDN

FAULT

EN

FLT

UNDERVOLTAGE

FB

DC-DC

CONVERTER

GND

SHDN

4.99k

383k

100k

102k

100ms/DIV

LT4356-3TA01b

20V/DIV

20V/DIV

80V INPUT SURGE

27V ADJUSTABLE CLAMP

12V

12V

TYPICAL APPLICATION

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