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LTC1504A

500mA Low Voltage

Step-Down Synchronous

Switching Regulator

Daisy-Chained Control Outputs

FEATURES

The LTC

chronous buck switching regulator. It includes a pair of

on-chip 1.3

Ω power switches, enabling it to supply up to

500mA of load current. Efficiency peaks at 92%, minimiz-

ing heat and wasted power. The synchronous buck archi-

tecture allows the output to source or sink current as

required to keep the output voltage in regulation. 100%

duty cycle operation minimizes dropout voltage.

The LTC1504A is available in adjustable and fixed 3.3V

output versions. An adjustable current limit circuit pro-

vides protection from overloads. The internal 1% refer-

ence combined with a sophisticated voltage feedback loop

provides optimum output voltage accuracy and fast load

transient response. The LTC1504A is specified to operate

with input voltages between 4V and 10V. Contact the LTC

factory for guaranteed specifications at 2.7V supply.

The LTC1504A is a pin-compatible, functional upgrade to

the LTC1504.

The LTC1504A is available in a plastic SO-8 package.

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500mA Output Current at 3.3V Output

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Up to 92% Peak Efficiency

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100% Maximum Duty Cycle

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Internal Reference Trimmed to 1%

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Output Can Source or Sink Current

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Requires as Few as Four External Components

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Input Voltage Range: 4V to 10V

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Adjustable Current Limit

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Small SO-8 Package

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200kHz Switching Frequency Can Typically be

Synchronized Up to 500kHz

Minimum Part Count 5V to 3.3V Regulator

5V to 3.3V Efficiency

LOAD CURRENT (mA)

10

100

90

80

70

60

50

40

30

20

10

0

100

500

1504 • TA02

SHDN

SS

COMP

GND

SW

SENSE

+

5V

SHUTDOWN

NC

NC

1000pF

+

3.3V AT 500mA

50

µH

1504A • TA01

LTC1504A-3.3

22

µF

47

µF

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Small Portable Digital Systems

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Active Termination

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Auxiliary Output Voltage Supplies

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Minimum Part Count/Size Switchers

, LTC and LT are registered trademarks of Linear Technology Corporation.