SM8136A

SEIKO NPC CORPORATION —1

White LED Driver IC

OVERVIEW

The SM8136A is a charge pump type white LED driver. It can drive 1 to 3 backlight white LED connected in

parallel, making it ideal for portable devices with small LCD. The charge pump switches between

×1 bypass

mode to

×1.5 boost mode in response to LED drive current requirements. The boost switching occurs in

response to the drive current of all the connected LED and thus supports variations in LED forward-bias volt-

age drop (VF). Besides, the detection of switching is repeated in approx. 1sec-cycle by mode reset action, the

SM8136A can respond to temporary variation of supply voltage. These ingenuities on switching detection can

prolong the battery life to the fullest extent. Each LED drive current is controlled by a 3-channel LED drive

current control circuit.

FEATURES

I

Battery life extension by automatic charge pump

switch between

×1 to ×1.5 according to the detec-

tion of the LED drive current

I

Controlling 1 to 3 lights of white LED connected

in parallel

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1-wire input controlling

I

ON/OFF and brightness control by signal control-

ling of EN pin

I

Soft start circuit built-in

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Input voltage range

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Maximum output voltage: 5.0V (typ)

I

Maximum output current: 60mA (typ)

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Quiescent current

Not-switching (

×1 mode): 0.3mA (typ)

Switching (

×1.5 mode): 1.0mA (typ)

I

Standby current: 0.01

µA (typ)

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Operating frequency (boost mode): 1.0MHz (typ)

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LED drive current accuracy between channel:

± 5.0%

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Package: 12-pin QFN

APPLICATIONS

I

Cellular phone

I

PDA

I

Portable games

I

Portable audio equipment

I

Handy terminal

I

Digital still camera

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Digital video camera

I

LCD panel back light

I

White LED driving

ORDERING INFORMATION

PINOUT

(Top view)

PACKAGE DIMENSIONS

(Unit: mm)

Device

Package

SM8136AB

12-pin QFN

EN

VOUT

C1P

NC

GND

VIN

A

B

A

S

0.10

8

−C0.08

C0.30

MS A B

φ0.05

0.40

× 2 = 0.80 ± 0.05

Top view

Bottom view

S

0.05

0.40

S

0.10

B

S

2.00

± 0.07

0.18

± 0.05

0.60

1.00

11

12

12