LT4356MP-1 Datasheet, PDF (1/20 Pages) Linear Technology – Surge Stopper

FEATURES
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, LT4356-1}
n _{Adjustable Fault Timer}
n _{Controls N-channel MOSFET}
n _{Shutdown Pin Withstands –60V to 100V}
n _{Fault Output Indication}
n _{Guaranteed Operation –55°C to 125°C}
n _{Spare Amplifier for Level Detection Comparator or}
Linear Regulator Controller
n _{Available in 10-Pin MSOP or 16-Pin SO Packages}
APPLICATIONS
n _{Automotive/Avionic Surge Protection}
n _{Hot Swap/Live Insertion}
n _{High Side Switch for Battery Powered Systems}
n _{Intrinsic Safety Applications}
L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
LT4356MP-1/LT4356MP-2
Surge Stopper
DESCRIPTION
The LT^®4356 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 LT4356MP also monitors the
voltage drop between the V_CC 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. After a cooldown period, the GATE
pin pulls up turning on the MOSFET again.
The spare 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. A shutdown pin reduces the quiescent current
to less than 7μA during shutdown for the LT4356-1 and
60μA for the LT4356-2 while keeping the reference and
auxiliary amplifier functioning.
TYPICAL APPLICATION
4A, 12V Overvoltage Output Regulator
V_IN
10mΩ IRLR2908
V_OUT
12V
383k
100k
UNDERVOLTAGE
10Ω
V_CC
SHDN
IN⁺
SNS GATE OUT
FB
LT4356S
A_OUT
GND
EN
TMR ^FLT
4356mp12 TA01
0.1μF
102k
4.99k
V_CC
DC-DC
CONVERTER
SHDN _GND
FAULT
Overvoltage Protector Regulates Output at
27V During Transient
80V INPUT SURGE
C_TMR = 6.8μF
I_LOAD = 500mA
V_IN
20V/DIV
12V
V_OUT
20V/DIV
12V
27V ADJUSTABLE CLAMP
100ms/DIV
4356mp12 TA01b
4356mp12f
1