SM8122A

NIPPON PRECISION CIRCUITS INC.—1

White LED Driver IC

OVERVIEW

The SM8122A is a high efficiency step-up DC/DC converter. Due to high voltage CMOS process realizing

25V output supply as maximum value, 2 to 6 lights of white LED connected in series can be lighted. By con-

necting in series, current variation among LED is eliminated. Current value sent to white LED can be set by

external resistors. In addition, brightness can also be adjusted by control to FB pin or CE pin. Since the

SM8122A has an over voltage protection circuit built-in, it dispenses with the existing external ZD (zener

diode). Besides, the switching frequency of the SM8122A is higher (2.0MHz) than the existing product

(SM8121A), so that it can respond to lower inductance value.

FEATURES

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Boost-up control using PWM

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2 to 6 lights of white LED (connected in series)

lighted

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Output current value can be set by external resis-

tors (51

Ω: 9.8mA, 33Ω: 15.2mA, 24Ω: 20.8mA)

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Brightness adjustable by control to FB pin or CE

pin

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Current variation among LED decreased by high

precision

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High efficient drive by step-up model

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Over voltage protection circuit built-in

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Supply voltage range: 2.3 to 5.5V

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Maximum output voltage: 25V

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Quiescent current: 820

µA (typ)

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Standby current: 1.0

µA (max)

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Switching frequency: 2.0MHz (typ)

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Output current detection accuracy:

± 2%

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Package: SOT23-6W (SM8122AH)

MSON-6 (SM8122AD)

APPLICATIONS

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Cellular phone

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Pager

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Digital still camera

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Handy terminal

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PDAs

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Portable games

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White LED drive

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LCD bias supply

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Flash memory supply

ORDERING INFORMATION

PINOUT

(Top view)

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SOT23-6W

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MSON-6

Device

Package

SM8122AH

SOT23-6W

SM8122AD

MSON-6

SW

VOUT

FB

1

2

3

VDD

CE

6

4

VSS

5

6

4

3

1

CE

SW

VDD

2

VOUT

5

VSS

FB