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LT1613

1.4MHz, Single Cell DC/DC

Converter in 5-Lead SOT-23

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Uses Tiny Capacitors and Inductor

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Internally Compensated

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Fixed Frequency 1.4MHz Operation

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3V at 30mA from a Single Cell

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5V at 200mA from 3.3V Input

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15V at 60mA from Four Alkaline Cells

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High Output Voltage: Up to 34V

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Low Shutdown Current: <1

µA

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Tiny 5-Lead SOT-23 Package

The LT

mode DC/DC converter. Intended for small, low power

applications, it operates from an input voltage as low as

1.1V and switches at 1.4MHz, allowing the use of tiny, low

cost capacitors and inductors 2mm or less in height. Its

small size and high switching frequency enables the

complete DC/DC converter function to take up less than

0.2 square inches of PC board area. Multiple output power

supplies can now use a separate regulator for each output

voltage, replacing cumbersome quasi-regulated ap-

proaches using a single regulator and a custom trans-

former.

A constant frequency, internally compensated current

mode PWM architecture results in low, predictable output

noise that is easy to filter. The high voltage switch on the

LT1613 is rated at 36V, making the device ideal for boost

converters up to 34V as well as for Single-Ended Primary

Inductance Converter (SEPIC) and flyback designs. The

device can generate 5V at up to 200mA from a 3.3V supply

or 5V at 175mA from four alkaline cells in a SEPIC design.

The LT1613 is available in the 5-lead SOT-23 package.

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Digital Cameras

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Pagers

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Cordless Phones

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Battery Backup

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LCD Bias

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Medical Diagnostic Equipment

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Local 5V or 12V Supply

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External Modems

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PC Cards

Efficiency Curve

LOAD CURRENT (mA)

0

50

100 150 200 250 300 350 400

1613 TA01a

100

95

90

85

80

75

70

65

60

55

50

Figure 1. 3.3V to 5V 200mA DC/DC Converter

3.3V

5V

200mA

1613 TA01

SW

L1

4.7

µH

D1

GND

LT1613

L1: MURATA LQH3C4R7M24 OR SUMIDA CD43-4R7

C1: AVX TAJA156M010

C2: AVX TAJB226M006

D1: MBR0520

C1

15

µF

C2

22

µF

R2

12.1k

R1

37.4k

FB

SHDN

SHDN

+

+

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

APPLICATIO S

FEATURES

TYPICAL APPLICATIO

DESCRIPTIO