SM8121A

NIPPON PRECISION CIRCUITS INC.—1

White LED Driver IC

OVERVIEW

The SM8121A 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.

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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Supply voltage range: 2.3 to 5.5V

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Maximum output voltage: 25V

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Quiescent current: 400

µA (typ)

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Standby current: 1.0

µA (max)

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Switching frequency: 1.0MHz (typ)

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Output current detection accuracy:

± 2%

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Small package: SOT23-5 (SM8121AH)

SON-6 (SM8121AD)

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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SOT23-5

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SON-6

Device

Package

SM8121AH

SOT23-5

SM8121AD

SON-6

SW

VSS

FB

1

2

3

VDD

CE

5

4

SW

VSS

FB

1

3

VDD

CE

6

4

VSS