LT4356-3
Surge Stopper with
Fault Latchoff
FEATURES
DESCRIPTION
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
loadstocontinuefunctioning.TheLT4356-3alsomonitors
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Stops High Voltage Surges
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Adjustable Output Clamp Voltage
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Overcurrent Protection
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Wide Operation Range: 4V to 80V
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Reverse Input Protection to –60V
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Low 7μA Shutdown Current
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Adjustable Latchoff Fault Timer
the voltage drop between the V and SNS pins to protect
CC
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Controls N-channel MOSFET
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.
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Shutdown Pin Withstands –60V to 100V
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Fault Output Indication
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Spare Amplifier for Level Detection Comparator or
Linear Regulator Controller
Available in (4mm × 3mm) 12-Pin DFN,
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10-Pin MSOP or 16-Pin SO Packages
The spare amplifier may be used as a voltage detection
comparator or as a linear regulator controller driving an
external PNP pass transistor.
APPLICATIONS
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Automotive/Avionic Surge Protection
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Hot Swap/Live Insertion
Back-to-back FETs can be used in lieu of a Schottky diode
for reverse input protection, reducing voltage drop and
powerloss. Ashutdownpinreducesthequiescentcurrent
to less than 7μA during shutdown.
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High Side Switch for Battery Powered Systems
Intrinsic Safety Applications
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L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
TYPICAL APPLICATION
4A, 12V Overvoltage Output Regulator
Overvoltage Protector Regulates Output at
27V During Transient
10mΩ
IRLR2908
V
OUT
V
IN
12V
C
LOAD
= 6.8μF
= 500mA
80V INPUT SURGE
TMR
I
10Ω
102k
V
IN
V
SNS GATE OUT
FB
20V/DIV
CC
383k
V
CC
SHDN
12V
12V
4.99k
27V ADJUSTABLE CLAMP
100ms/DIV
DC-DC
+
IN
LT4356DE-3
V
OUT
CONVERTER
20V/DIV
100k
EN
SHDN
GND
UNDERVOLTAGE
A
FLT
FAULT
LT4356-3TA01b
OUT
GND
TMR
43563 TA01
0.1μF
43563f
1