LM3590

Series White LED Driver

General Description

The LM3590 is a White LED constant current driver capable

of supplying up to 3 White LEDs connected in series with

20mA. This device operates over a wide 6V-12.6V input

voltage range. The output can accomodate LEDs with a

combined forward voltage of up to 11.5V, from a 12V input

supply. The LED drive current is programmed by using an

external resistor on the I

LED brightness can be linearly varied up to the programmed

LED current by applying a Pulse Width Modulated (PWM)

signal to the EN pin of the device. The LED output current of

the LM3590 is tightly controlled over temperature and volt-

age. LED Current matching is guaranteed due to the series

configuration of the LEDs. The series topology also simpli-

fies the connection between the White LEDs in the display

module and the LM3590 since only one connection is re-

quired.

The LM3590 typically draws only 50µA when operating in the

no-load condition and draws less than 0.1µA when the de-

vice is shut down.

The LM3590 is available in a small 5-pin SOT23 package.

Features

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Drives up to 3 stacked white LEDs

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6.0V-12.6V input voltage range

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Up to 20mA LED output current

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Excellent LED current matching guaranteed by series

configuration

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Single connection to the White LEDs in the display

module

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Tightly controlled programmable current source

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Low shutdown current (0.1µA typ.)

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PWM brightness control

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Very small solution size

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SOT23-5 package: 3mm x 3mm x 1.0mm (LxWxH)

Applications

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White LED Display Backlights

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Keypad Backlights

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General purpose constant current driver for high

forward-voltage LEDs

Typical Application Circuit

20081301

20081305

November 2003

© 2003 National Semiconductor Corporation

DS200813

www.national.com