LTC3561A

1

3561af

TYPICAL APPLICATION

FEATURES

APPLICATIONS

DESCRIPTION

1A, 4MHz, Synchronous

Step-Down DC/DC Converter

The LTC

step-down DC/DC converter. Intended for medium power

applications, it operates from a 2.5V to 5.5V input voltage

range and has a user configurable operating frequency up

to 4MHz, allowing the use of tiny, low cost capacitors and

inductors 1mm or less in height. The output voltage is

adjustable from 0.8V to 5.5V. Internal synchronous power

switches provide high efficiency. The LTC3561A’s current

mode architecture and external compensation allow the

transient response to be optimized over a wide range of

loads and output capacitors.

To further maximize battery life, the P-channel MOSFET

is turned on continuously in dropout (100% duty cycle).

In shutdown, the device draws <1μA.

Step-Down 2.5V/1A Regulator

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Uses Tiny Capacitors and Inductor

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High Frequency Operation: Up to 4MHz

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High Efficiency: Up to 96%

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Stable with Ceramic Capacitors

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Current Mode Operation for Excellent Line

and Load Transient Response

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Short-Circuit Protected

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Low Dropout Operation: 100% Duty Cycle

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Low Quiescent Current: 330μA

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Output Voltages from 0.8V to 5V

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Small 8-Lead 3mm

× 3mm DFN Package

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Notebook Computers

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Digital Cameras

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Cellular Phones

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Handheld Instruments

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Board Mounted Power Supplies

Efficiency and Power Loss vs Output Current

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

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

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

OUTPUT CURRENT (mA)

110

0

40

30

100

1

0.1

0.01

0.001

0.0001

1000

100

10000

3561A TA01b

20

10

60

50

80

70

90

LTC3561A

SW

PGND

SGND

2.2μH

2.5V

1A

2.5V TO 5.5V

249k

22pF

118k

680pF

3561a TA01a

22μF

16.9k

10μF

549k