SM8134A

SEIKO NPC CORPORATION —1

White LED Driver IC

OVERVIEW

The SM8134A is a charge pump type white LED driver. It can drive 1 to 4 backlight white LED connected in

parallel and 1 flash white LED, making the device ideal for camera-equipped cellular phones. The charge

pump switches between

×1 to ×1.5 boost mode in response to LED drive current requirements to extend bat-

tery life to the maximum. The boost switching occurs in response to the drive current of all the connected LED

and thus supports variations in LED forward-bias voltage drop (VF). Each LED drive current is controlled by a

5-channel LED drive current control circuit. The backlight LED drive current and ON/OFF control, and flash

LED drive current and ON/OFF control are all set by 3-wire serial interface data input. Also, an under voltage

lockout (UVLO) circuit is built-in to prevent incorrect operation when the battery voltage drops.

FEATURES

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Noise reduction due to charge pump boost circuit

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Automatic charge pump switching to conserve

power

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Drives 1 to 4 backlight white LED

(30mA/ch at maximum setting)

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Drives a flash white LED

(150mA at maximum setting)

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Backlight and flash white LED brightness

adjustment

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3-wire serial input interface for all setting and

control

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Under voltage lockout (UVLO) circuit built-in

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Soft start circuit built-in

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Thermal protection circuit built-in

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Input voltage range

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Quiescent current

• Not-switching (

×1.0 mode): 0.3mA (typ)

• Switching (

×1.5 mode): 1.7mA (typ)

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Standby current: 0.01

µA (typ)

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Operating frequency: 750kHz (typ)

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Maximum backlight LED current: 30mA/ch

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Maximum flash LED current: 150mA

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All LED total maximum current: 200mA

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:

± 3%

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:

± 6.7%

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Packages: 16-pin QFN

PINOUT

(Top view)

PACKAGE DIMENSION

(Unit: mm)

APPLICATIONS

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Cellular phone

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Digital still camera

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PDA

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Portable games

ORDERING INFORMATION

Device

Package

SM8134AB

16-pin QFN

SDA

DIN1

VOUT

VIN

DIN3

DIN4

DIN5

PGND

TOP VIEW

BOTTOM VIEW

3.0 ± 0.08

0.22 ± 0.05

C 0.3

1.8

∆ 0.05 M

S

0.2 S AB

0.5

B

SA

0.2 S

S

0.05

A

B