LTC3565

1

3565f

FEATURES

APPLICATIONS

DESCRIPTION

1.25A, 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 0.6V to 5.5V. Internal synchronous power

switches provide high efficiency. The LTC3565’s current

mode architecture and external compensation allow the

transient response to be optimized over a wide range of

loads and output capacitors.

The LTC3565 can be configured for automatic power

charge losses when the load current drops below the level

required for continuous operation. For reduced noise and

RF interference, the SYNC/MODE pin can be configured to

skip pulses or provide forced continuous operation.

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/1.25A Regulator

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High Efficiency: Up to 95%

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High Frequency Operation: Up to 4MHz

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Burst Mode

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Stable with Ceramic Capacitors

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Uses Tiny Capacitors and Inductor

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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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Output Voltages from 0.6V to 5V

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Synchronizable to External Clock

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Supports Pre-Biased Outputs

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Small 10-Lead (3mm × 3mm) DFN or MSOP 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

SYNC/MODE

LTC3565

SW

RUN

PGOOD

ITH

RT

GND

2.2μH

2.5V

1.25A

2.5V TO 5.5V

22pF

931k

294k

680pF

3565 TA01a

22μF

12.1k

22μF

191k

, LT, LTC, LTM 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 5481178, 6580258, 6498466, 6611131.

OUTPUT CURRENT (mA)

0.1

1

10

0

40

30

100

1

0.1

0.01

0.001

0.0001

1000

100

10000

3565 TA01b

20

10

60

50

80

70

90

Efficiency and Power Loss vs Output Current

TYPICAL APPLICATION