POWER MANAGEMENT

1

SC618

Charge Pump Flash LED

Driver with Safety Timer

Features

Flash and spotlight — two selectable modes

Flash mode — up to 700mA output

Flash mode — 500mA max output (over rated voltage,

temperature, and load conditions)

Flash mode safety timer shut-off — 1 second

Spotlight mode set to 40% of flash current

Spotlight mode — up to 280mA output

Spotlight mode —1x mode (under most conditions)

for best efficiency

Input range — 3.0V to 5.25V

External flash control pin for synchronization to a cam-

era module or graphics controller

Short-circuit, over-voltage, and over-temperature pro-

tection

Soft-start functionality

Separate flash and spotlight control inputs for maxi-

mum versatility

Ultra-thin package MLPD-UT-10 — 3mm x 3mm x

0.6mm

Applications

Mobile camera phones

Digital cameras

PDAs with built-in cameras

Description

The SC618 is a high-current charge pump designed spe-

cifically for use with white LEDs used in camera flash

applications. Only two small bucket capacitors are required

to develop the output drive, providing a low EMI solution

compared to inductive boost regulators.

The SC618 has two modes of operation: flash mode and

spotlight mode. In flash mode, the SC618 is capable of

delivering 500mA of regulated current for a duration of

500ms or up to 700mA for a reduced duration. A safety

timer is also included to ensure the LED cannot be left on

indefinitely and overheat. In spotlight mode the SC618

outputs 40% of the flash mode current and can remain

enabled continuously.

An external resistor is connected in series with the LED to

set the current. In flash mode, this resistor can dissipate

up to 175mW, reducing the power dissipation require-

ment of the SC618. The flash input overrides the control

input to make sure the flash function is activated .

The SC618 ultra-thin package provides both a low profile

and high thermal efficiency.

SC618

VIN

C2-

C2+

C1-

C1+

VOUT

FLASH

CTRL

GND

ISET

1μF

1μF

FLASH

CTRL

1μF

10μF

White LED

Typical Application Circuit

February 6, 2008