1

LTC1872

APPLICATIO S

FEATURES

DESCRIPTIO

Constant Frequency

Current Mode Step-Up

DC/DC Controller in SOT-23

The LTC

up DC/DC controller providing excellent AC and DC load

and line regulation. The device incorporates an accurate

undervoltage lockout feature that shuts down the LTC1872

when the input voltage falls below 2.0V.

The LTC1872 boasts a

±2.5%outputvoltageaccuracyand

consumes only 270

µA of quiescent current. For applica-

tions where efficiency is a prime consideration, the LTC1872

is configured for Burst Mode operation, which enhances

efficiency at low output current.

In shutdown, the device draws a mere 8

µA. The high

550kHz constant operating frequency allows the use of a

small external inductor.

The LTC1872 is available in a small footprint 6-lead

SOT-23.

s

Lithium-Ion-Powered Applications

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Cellular Telephones

s

Wireless Modems

s

Portable Computers

s

Scanners

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High Efficiency: Over 90%

s

High Output Currents Easily Achieved

s

s

s

Constant Frequency 550kHz Operation

s

Burst Mode

s

Current Mode Operation for Excellent Line and Load

Transient Response

s

Low Quiescent Current: 270

µA

s

Shutdown Mode Draws Only 8

µA Supply Current

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±2.5% Reference Accuracy

s

Tiny 6-Lead SOT-23 Package

Efficiency vs Load Current

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

Burst Mode is a trademark of Linear Technology Corporation.

LTC1872

147k

422k

80.6k

R1

0.03

Ω

L1

4.7

µH

220pF

C1: TAIYO YUDEN CERAMIC EMK325BJ106MNT

C2: MURATA GRM42-2X5R226K6.3

D1: IR10BQ015

L1: MURATA LQN6C4R7M04

M1: IRLMS2002

R1: DALE 0.25W

GND

5

4

6

1872 TA01

1

2

3

NGATE

C1

10

µF

10V

3.3V

5V

1A

C2

2

× 22µF

6.3V

+

M1

D1

Figure 1. LTC1872 High Output Current 3.3V to 5V Boost Converter

LOAD CURRENT (mA)

1

100

95

90

85

80

75

70

65

10

100

1000

1872 TA01b