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LTC1477/LTC1478

The LTC

protection against short-circuit and thermal overload con-

ditions. A built-in charge pump generates gate drive

higher than the supply voltage to fully enhance the internal

NMOS switch. This switch has no parasitic body diode and

therefore no current flows through the switch when it is

turned off and the output is forced above the input supply

voltage. (DMOS switches have parasitic body diodes that

become forward biased under these conditions.)

Two levels of protection are provided by the

LTC1477/LTC1478. The first level of protection is short-

circuit current limit which is set at 2A. The short-circuit

current can be reduced to as low as 0.85A by disconnect-

ing portions of the power device (see Applications Infor-

mation). The second level of protection is provided by

thermal overload protection which limits the die tempera-

ture to approximately 130

°C.

The LTC1477 single is available in 8-lead SO packaging.

The LTC1478 dual is available in 16-lead SO packaging.

Single and Dual Protected

High Side Switches

FEATURES

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No Parasitic Body Diode

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Built-In Short-Circuit Protection: 2A

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Built-In Thermal Overload Protection

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Operates from 2.7V to 5.5V

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Inrush Current Limited

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Ultralow Standby Current: 0.01

µA

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Built-In Charge Pump

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Single Switch in 8-Pin SO Package

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Dual Switch in Narrow 16-Pin SO Package

CHARGE

PUMP

GATE CHARGE

AND

DISCHARGE

CONTROL LOGIC

CURRENT LIMIT

AND THERMAL

SHUTDOWN

EN

LTC1477/1478 • TA01

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*NMOS SWITCHES WITH NO PARASITIC BODY DIODES

, LTC and LT are registered trademarks of Linear Technology Corporation.

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Notebook Computer Power Management

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Power Supply/Load Protection

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Supply/Battery Switch-Over Circuits

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Circuit Breaker Function

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"Hot Swap" Board Protection

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Peripheral Power Protection

Switch Output Voltage

OUTPUT CURRENT (A)

0

4.60

4.70

4.80

4.90

5.00

5.20

0.25

0.5

0.75

1.00

LTC1477/1478 • TP02

1.25

1.50

5.10