LT3486

1

3486f

■

Wide (1000:1) PWM Dimming Range with No

ColorShift

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Independent Dimming and Shutdown Control of the

LED Drivers

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Drives Up to 16 White LEDs at 25mA (8 per Driver)

from a Single Li-Ion Cell

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Drives Up to 16 White LEDs at 100mA (8 per Driver)

from 12V Supply

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±3% LED Current Programming Accuracy

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Open LED Protection: 36V Clamp Voltage

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Fixed Frequency Operation: Up to 2MHz

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Wide Input Voltage Range: 2.5V to 24V

■

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Overtemperature Protection

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Available in (5mm × 3mm × 0.75mm) 16-Pin DFN

and 16-Pin Thermally Enhanced TSSOP Packages

Dual 1.3A White LED

Step-Up Converters with

Wide Dimming

specifically designed to drive up to 16 White LEDs (8 in

series per converter) at constant current from a single

Li-Ion cell. Series connection of the LEDs provides identi-

cal LED currents resulting in uniform brightness. The two

independent converters are capable of driving asymmetric

LED strings.

The dimming of the two LED strings can be controlled

independently via the respective CTRL pins. An internal

dimming system allows the dimming range to be extended

up to 1000:1 by feeding a PWM signal to the respective

PWM pins. The LT3486 operating frequency can be set with

an external resistor over a 200kHz to 2MHz range. A low

200mV feedback voltage (±3% accuracy) minimizes power

loss in the current setting resistor for better efficiency.

Additional features include output voltage limiting when

LEDs are disconnected and overtemperature protection.

The LT3486 is available in a space saving 16-pin DFN

(5mm × 3mm × 0.75mm) and 16-pin thermally enhanced

TSSOP packages.

Li-Ion Powered Driver for Camera Flash and LCD Backlighting

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

All other trademarks are the property of their respective owners. Patent Pending.

FEATURES

DESCRIPTIO

APPLICATIO S

TYPICAL APPLICATIO

■

Notebook PC Display

■

LED Camera Light for Cell Phones

■

Car Dashboard Lighting

■

Avionics Displays

3

65

70

75

80

85

90

3.2

3.4

3.6

3.8

3486 TA01b

4

4.2

MOVIE MODE

FLASH MODE

8 LEDS/25mA

3V TO 4.2V

10

µF

L1

10

µH

L2

10

µH

0.1

µF

2.2

µF

63.4k

2.8k

4.7nF

8.06

Ω

0.62

Ω

2.2

µF

0.1

µF

3486 TA01a

100k

LED1

AOT3218

25mA

8 LEDs

OFF ON

OFF ON

DIMMING 2

SW1

SW2

LT3486

OVP2

CTRL2

REF

PWM2

FB2

OVP1

CTRL1

SHDN

PWM1

FB1

DIMMING 1