LTC3609



3609fb

Typical applicaTion

FeaTures

applicaTions

DescripTion

32V, 6A Monolithic

Synchronous Step-Down

DC/DC Converter

step-downDC/DCconverterthatcandeliverupto6Aoutput

current from a 4V to 32V (36V maximum) input supply. It

uses a valley current control architecture to deliver very

low duty cycle operation at high frequency with excellent

transient response. The operating frequency is selected

by an external resistor and is compensated for variations

The LTC3609 can be configured for discontinuous or

forced continuous operation at light load. Forced continu-

ous operation reduces noise and RF interference while

discontinuous mode provides high efficiency by reducing

switching losses at light loads.

Fault protection is provided by internal foldback current

limiting,anoutputovervoltagecomparatorandanoptional

short-circuit shutdown timer. Soft-start capability for sup-

ply sequencing is accomplished using an external timing

capacitor.Theregulatorcurrentlimitisuserprogrammable.

A power good output voltage monitor indicates when

the output is in regulation. The LTC3609 is available in a

compact 7mm

× 8mm QFN package.

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6AOutputCurrent

n

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InternalN-ChannelMOSFETs

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TrueCurrentModeControl

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OptimizedforHighStep-DownRatios

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ExtremelyFastTransientResponse

n

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±1%0.6VVoltageReference

n

Power Good Output Voltage Monitor

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Adjustable On-Time/Switching Frequency

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Adjustable Current Limit

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Programmable Soft-Start

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Output Overvoltage Protection

n

Optional Short-Circuit Shutdown Timer

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Available in a 7mm

× 8mm 52-Pin QFN Package

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Point of Load Regulation

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Distributed Power Systems

1.2µH

4.7µF

10µF

x3

4V TO 32V

2.5V

6A

3609 TA01a

187k

0.1µF

SW

BOOST

RUN/SS

SGND

FCB

PGND

0.22µF

100µF

x2

15.8k

LTC3609

1000pF

PGOOD

30.1k

9.53k

100pF

LOAD CURRENT (A)

0.01

80

90

70

0

50

40

30

20

10

60

0.1

1

10

100

1000

100

1

10

10000

POWER LOSS

EFFICIENCY

HighEfficiencyStep-DownConverter

EfficiencyandPowerLoss

vsLoadCurrent

L

, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear

Technology Corporation. All other trademarks are the property of their respective owners.

Protected by U.S. Patents, including 5481178, 6100678, 6580258, 5847554, 6304066.