1

LT1612

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Operates from Input Voltage As Low As 2V

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Internal 0.7A Synchronous Switches

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Uses Ceramic Input and Output Capacitors

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620mV Reference Voltage

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800kHz Fixed Frequency Switching

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Programmable Burst Mode Operation

The LT

DC converter that operates from an input voltage as low

as 2V. Internal 0.45

Ω switches deliver output currents up

to 500mA, and the 800kHz switching frequency allows the

use of small, low value ceramic input and output capaci-

tors. Input voltage ranges from 5.5V down to 2V and

output voltage can be set as low as the 620mV reference.

The device features Burst Mode

efficiency high at light loads. Burst Mode operation can be

defeated by pulling the MODE pin high, enabling constant

switching throughout the load range for low noise.

No-load quiescent current is 160

µAandshutdowncurrent

is less than 1

µA. The device is available in 8-lead SO and

MSOP packages.

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Portable Devices

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Lithium-Ion Step-Down Converters

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5V to 3.3V Conversion

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2-Cell Alkaline Step-Down Converters

Figure 1. 2V to 1.2V Converter

Synchronous, Step-Down

800kHz PWM

DC/DC Converter

April 2000

FEATURES

Final Electrical Specifications

Information furnished by Linear Technology Corporation is believed to be accurate and reliable.

However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-

tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.

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

Burst Mode is a trademark of Linear Technology Corporation.

2V

0.1

µF

33k

R2

232k

1%

R1

215k

1%

L1

10

µH

330pF

C1

10

µF

C2

68

µF

3.15V

C1: TAIYO-YUDEN JMK325BJ106MN

C2: PANASONIC EEFCDOF680R

L1: SUMIDA CD43-100

1612 F01a

1.2V

500mA

100pF

SW

FB

BOOST

MODE

SHDN

GND

LT1612

LOAD CURRENT (mA)

90

80

70

60

50

40

30

100

10

500

1612 • F01b

Efficiency for LT1612 vs Linear Regulator