LT3840

1

3840fa

For more information www.linear.com/LT3840

Typical applicaTion

FeaTures

DescripTion

Wide Input Range

Synchronous Regulator Controller

with Accurate Current Limit

The LT®3840 is a high voltage synchronous step-down

switching regulator controller capable of operating from

a 2.5V to 60V supply.

The LT3840’s low quiescent current, when configured for

user selectable Burst Mode operation, helps extend run

time in battery-powered systems by increasing efficiency

at light loads. The LT3840 uses a constant frequency,

current mode architecture. High current applications are

possible with large N-channel gate drivers capable of

An integrated buck-boost switching regulator generates

a 7.5V bias supply voltage for MOSFET gate drive and IC

power allowing higher efficiency operation over the entire

inputvoltagerangeandeliminatingtheneedforanexternal

bias voltage. An accurate current limit set point regulates

the maximum output current. A current monitor reports

the average output current.

High Efficiency Synchronous Step-Down Converter

applicaTions

L

, LT, LTC, LTM, Linear Technology, Burst Mode, and the Linear logo are registered

trademarks of Linear Technology Corporation. All other trademarks are the property of their

respective owners.

n

Wide Input Range: 2.5V to 60V

n

Integrated Buck-Boost Supply for 7.5V MOSFET

Gate Drive

n

Programmable Constant-Current Operation with

Current Monitor Output

n

n

Operation

n

n

Adjustable and Synchronizable: 50kHz to 1MHz

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Internal OVLO Protects for Input Transients Up to 80V

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Accurate Input Overvoltage and Undervoltage Threshold

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Programmable Soft-Start with Voltage Tracking

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Power Good and Output OVP

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28-Lead TSSOP and 38-Lead 4mm × 6mm QFN Packages

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Automotive Supplies

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Industrial Systems

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Distributed DC Power Systems

LOAD CURRENT (A)

0

100

95

80

75

90

85

70

50

65

60

55

10

5

15

3840 TA01b

20

ICOMP

ICTRL

IMON

AUXSW2

AUXSW1

AUXBST

LT3840

3840 TA01a

BOOST

TG

SW

BG

FB

GND

4V TO 60V

68µF

×2

330µF

×2

49.9k

20k

7.68k

10k

16.9k

1500pF

2200pF

470pF

100pF

1µF

1µF

1.5µH

2m

4.7µF

33µH

EN

TK/SS

AUXVIN

UVLO

OVLO

PG

SYNC

MODE

RT

3.3V

20A