LTC4381

1

Rev. 0

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TYPICAL APPLICATION

FEATURES

DESCRIPTION

Low Quiescent Current Surge

Stopper with 9mΩ MOSFET

The LTC®4381 is an integrated solution for low quiescent

current surge stopper applications that protect loads from

high voltage transients. Overvoltage protection is pro-

vided by clamping the gate voltage of an internal 9mΩ

N-channel MOSFET to limit the output voltage to a safe

value during overvoltage events such as load dump in

automobiles. The MOSFET safe operating area is pro-

duction tested and guaranteed for the stresses during

high voltage transients. Fixed output clamp voltages are

selectable for 12V and 24V/28V systems. For systems of

any voltage up to 80V, use the adjustable clamp versions.

Overcurrent protection is also provided. An internal mul-

overvoltage conditions is limited in accordance with

MOSFET stress.

The GATE pin can drive back-to-back MOSFETs for

reverse input protection, eliminating the voltage drop

and dissipation of a Schottky diode solution. A low 6µA

operating current permits use in always-on and battery

powered applications.

12V System with 100V/0.5A/400ms Load Dump Overvoltage Protection

12V, 0.5A with 100V Overvoltage Protection

APPLICATIONS

n

Withstands Surge Voltages Up to 100V

n

Internal 9mΩ N-Channel MOSFET

n

Guaranteed Safe Operating Area: 20ms at 70V, 1A

n

Low Quiescent Current: 6µA Operating

n

Operates Through Automobile Cold Crank

n

Wide Operating Voltage Range: 4V to 72V

n

Overcurrent Protection

n

Selectable Internal 28.5V/47V or Adjustable Output

Clamp Voltage (Table 1)

n

Reverse Input Protection to –60V

n

Adjustable Turn-On Threshold

n

Adjustable Fault Timer with MOSFET Stress

Acceleration

n

Latchoff and Retry Options (Table 1)

n

Low Retry Duty Cycle During Faults (Table 1)

n

32-Lead DFN (7mm × 5mm) Package

n

Automotive 12V, 24V and 48V System

n

Avionic/Industrial Surge Protection

n

Hot Swap/Live Insertion

n

High Side Switch for Battery Powered Systems

n

Automotive Load Dump Protection

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100V INPUT SURGE

100ms/DIV

20V/DIV

20V/DIV

4381 TA01b

12V

12V

4381 TA01a

200k

20k

0.1µF

68V

10µF

80m

33

47nF

10

22µF

IN

DRN

ON

SEL

GND

TMR

SRC

SNS

OUT

LTC4381-2

GATE

GFET

CMHZ5266B

12V/0.5A

OUTPUT

CLAMPED

AT 28.5V

12V

FLT