LM3595

Parallel White-LED Driver

General Description

The LM3595 is a parallel white-LED driver that is capable of

driving four white LEDs. It can supply a total output current of

100mA over an input voltage range of 3.0V to 5.5V. The

amount of constant current sourced to the outputs is user

selectable using one external sense resistor.

LM3595 typically draws 0.03µA when placed in shutdown,

and 200µA when operating in the no-load condition. If any of

the outputs are not used, leave the pin(s) unconnected.

Brightness can be controlled by both analog and PWM tech-

niques. A voltage between 0V and 3V may be applied to the

BRGT pin to vary the current. Output current will linearly

track the voltage applied to the BRGT pin. An active-low

level must be present on the BR-ON pin for analog bright-

ness control to be disabled. Alternatively, a PWM signal can

be applied to the EN pin to vary the perceived brightness of

the LED.

The LM3595 uses an active-high enable level. The LM3595

is available in National’s LLP-10 package.

Features

n

Regulated I

current outputs

n

Drives one, two, three or four white LED’s with no bias

resistors

n

3.0V to 5.5V Input voltage

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Up to 100mA output current

n

Active-High Enable Pin

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Analog Brightness Control

n

Very small solution size

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LLP-10 package: 3.0mm x 3.0mm x 0.8mm

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Very Low Shutdown current (0.03µA typ.)

Applications

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Portable devices using white or blue LEDs with display

and backlight or frontlight

n

Keypad LEDs

n

Strobe LEDs

Typical Application Circuit

20072201

August 2003

© 2003 National Semiconductor Corporation

DS200722

www.national.com