April 2006

Rev. 2

1/14

14

STLD40D

White led power supply for large display backlight

General Features

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Inductor switches boost controller

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PFM mode control

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High efficiency over wide range of input voltage

from 3.0V to 5.5V

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Overvoltage protection with automatic restart

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Adjustable peak current limit

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Enable pin with possibility of PWM dimming

control

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Low shutdown current <1uA

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Small external component

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Good load and line regulation

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QFN 3mm x 3mm x 1mm 8 leads

Application

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White Led supply for LCD backlight

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Mobile phone

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PDA and organizers

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Any handsets powered form 3.0V to 5.5V

Description

STLD40D is a boost converter that operates from

3.0V to 5.5V and can provide an output voltage as

high as 37V and can drive up to 10 white LEDs in

series. The converter is a PFM (pulse frequency

modulation) inductor switches and can work in

discontinuous (DCM) mode operation. A minimum

fixed internally and allows limiting the switching

frequency. The output current capability is 20mA

with an output voltage of 37V.

The regulation is done by sensing the led current

The device can be turned ON/OFF through the

logic enable signal pin EN. By applying a low

frequency PWM signal the LEDs can be dimmed.

The maximum peak inductor current can be

www.st.com

QFN8 (3mm x 3mm)

Order code

Part number

Package

Comments

STLD40DPMR

QFN8L (3mm x 3mm)

4500 parts per reel