LTC3215EDD 查看數據表（PDF） - Linear Technology

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LTC3215EDD

700mA Low Noise High Current LED Charge Pump

Linear Technology 

FEATURES

n High Efficiency Operation: 1x, 1.5x or 2x Boost

Modes with Automatic Mode Switching

n Ultralow Dropout ILED Current Control

n Output Current up to 700mA

n Low Noise Constant Frequency Operation*

n Wide VIN Range: 2.9V to 4.4V

n Open/Shorted LED Protection

n LED Disconnect in Shutdown

n Low Shutdown Current: 2.5µA

n 4% LED Current Programming Accuracy

n Automatic Soft-Start Limits Inrush Current

n No Inductors

n Tiny Application Circuit (All Components <1mm

Profile)

n 3mm × 3mm 10-Lead DFN Package

APPLICATIONS

n LED Torch/Camera Light Supply for Cell Phones,

PDAs and Digital Cameras

n General Lighting and/or Flash/Strobe Applications

LTC3215

700mA Low Noise High

Current LED Charge Pump

DESCRIPTION

The LTC®3215 is a low noise, high current charge pump

DC/DC converter designed to power high current LEDs.

The part includes an accurate programmable current source

capable of driving loads up to 700mA from a 2.9V to 4.4V

input. Low external parts count (two flying capacitors, one

programming resistor and two bypass capacitors) makes

the LTC3215 ideally suited for small, battery-powered

applications.

Built-in soft-start circuitry prevents excessive inrush cur-

rent during start-up. High switching frequency enables

the use of small external capacitors. LED current is pro-

grammed with an external resistor. The LED is disconnected

from VIN during shutdown.

An ultralow dropout current source maintains accurate

LED current at very low ILED voltages. Automatic mode

switching optimizes efficiency by monitoring the voltage

across the LED current source and switching modes only

when ILED dropout is detected. The LTC3215 is available

in a low profile 3mm × 3mm 10-Lead DFN package.

L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear

Technology Corporation. All other trademarks are the property of their respective owners.

Protected by U.S. Patents, including 6411531.

TYPICAL APPLICATION

C1

2.2µF

C2

2.2µF

2.9V TO 4.4V

CIN

2.2µF

DISABLE ENABLE

C1+ C1– C2+ C2–

VIN

CPO

LTC3215

ILED

EN

ISET

20k

1%

3215 TA01a

LED1: AOT2015

LED1

ILED

200mA

CCPO

4.7µF

Efficiency vs VIN

100

90

80

ILED = 200mA

70

60

50

40

30

20

10 LED = AOT2015

VF = 3V TYP AT 200mA

0

2.8 3.0 3.2 3.4 3.6 3.8 4.0 4.2 4.4

VIN (V)

3215 TA01b

3215fc

1

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