LTC3614

1

3614fc

Typical applicaTion

FeaTures

applicaTions

DescripTion

4A, 4MHz Monolithic

Synchronous Step-Down

DC/DC Converter

The LTC®3614 is a low quiescent current monolithic syn-

chronous buck regulator using a current mode, constant

frequency architecture. The no-load DC supply current

in sleep mode is only 75µA while maintaining the output

voltage (Burst Mode operation) at no load, dropping to

zero current in shutdown. The 2.25V to 5.5V input supply

voltage range makes the LTC3614 ideally suited for single

Li-Ionaswellasfixedlowvoltageinputapplications.100%

duty cycle capability provides low dropout operation,

extending the operating time in battery-powered systems.

The operating frequency is externally programmable up to

4MHz, allowing the use of small surface mount inductors.

For switching-noise-sensitive applications, the LTC3614

can be synchronized to an external clock at up to 4MHz.

ForcedcontinuousmodeoperationintheLTC3614reduces

noiseandRFinterference.Adjustablecompensationallows

the transient response to be optimized over a wide range

of loads and output capacitors.

The internal synchronous switch increases efficiency and

eliminates the need for an external catch diode, saving

external components and board space. The LTC3614

is offered in a leadless 24-pin 3mm

× 5mm thermally

enhanced QFN package.

L

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

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

Protected by U.S. Patents, including 6580258, 5481178, 5994885, 6304066, 6498466, 6611131.

Efficiency and Power Loss

vs Load Current

n

4A Output Current

n

2.25V to 5.5V Input Voltage Range

n

n

±1% Output Voltage Accuracy

n

Output Voltage Down to 0.6V

n

High Efficiency: Up to 95%

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Low Dropout Operation: 100% Duty Cycle

n

Programmable Slew Rate on SW Node Reduces

Noise and EMI

n

Adjustable Switching Frequency: Up to 4MHz

n

Optional Active Voltage Positioning (AVP) with

Internal Compensation

n

Selectable Pulse-Skipping/Forced Continuous/Burst

Mode Operation with Adjustable Burst Clamp

n

Programmable Soft-Start

n

Inputs for Start-Up Tracking or External Reference

n

n

Available in a 24-Pin 3mm

× 5mm QFN

Thermally Enhanced Package

n

Point-of-Load Supplies

n

Distributed Power Supplies

n

Portable Computer Systems

n

DDR Memory Termination

n

Handheld Devices

OUTPUT CURRENT (mA)

30

90

100

20

10

80

50

70

60

40

1

100

1000

10000

3614 TA01b

0

0

1

0.1

0.01

10

RUN

TRACK/SS

RT/SYNC

PGOOD

ITH

SGND

PGND

2.7V TO 5.5V

SRLIM/DDR

LTC3614

SW

330nH

665k

210k

3614 TA01a

10µF

×4

MODE

47µF

×2

2.5V

4A