General Description

The MAX1582 drives up to six white LEDs in series with

a constant current to provide display backlighting for

two (main and sub-) displays in cell phones and other

hand-held devices. This configuration eliminates the

need for ballast resistors and expensive factory calibra-

tion. The proprietary dual-output, step-up pulse-width

N-channel MOSFET switch for high efficiency and maxi-

mum battery life.

The MAX1582 utilizes 1MHz current-mode PWM control

to allow small input and output capacitors and a small

inductor, while minimizing ripple on the input supply and

avoiding interference to sensitive circuitry in the equip-

ment. Integrated overvoltage protection eliminates the

need for an external zener diode to protect the IC from

open circuit. Flexible dimming control utilizes either an

analog control signal or direct digital PWM control with-

out external RC filtering. This also increases dimming

accuracy at low brightness levels. The PWM dimming

signal can be any frequency from 200Hz to 200kHz.

Soft-start eliminates inrush current during startup.

(UCSP™) and 12-pin thin QFN packages.

Applications

Cell Phones with One or Two Displays

Smart Phones, Palmtops, and Wireless

Handhelds

Other Hand-Held Devices with Dual Displays

Features

o Accurate Current Regulation for Uniform

Illumination

o Lights Up Two LED Sections for Main and

Subdisplays

o Up to 84% Efficiency

o Internal High-Power, 30V MOSFET

o Flexible Dimming Control

Analog DAC Controlled

Direct-Digital PWM (No RC Required)

from 200Hz to 200kHz

o Overvoltage Protection to Eliminate Zener Diode

o Constant 1MHz PWM Operation

o Low-Profile Inductor and Capacitors

o Soft-Start Eliminates Inrush Current

o 2.6V to 5.5V Input

o 0.01µA (typ) Shutdown Current

High-Efficiency, 26V Step-Up Converter

for White LED Main and Subdisplay Backlighting

________________________________________________________________ Maxim Integrated Products

1

Ordering Information

19-2783; Rev 0; 4/03

For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at

1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

EVALU

ATION

KIT

AVAIL

ABLE

PART

TEMP RANGE

PIN-PACKAGE

TOP

MARK

MAX1582ETC

-40

°C to +85°C 12 Thin QFN-EP*

AACE

MAX1582EBE-T-40

°C to +85°C 16 UCSP-16

1582EBE

Pin Configurations

MAX1582

INPUT

2.6V TO 5.5V

2.2

µF

0.022

µF

0.1

µF

V+

VP

CTRL

EN1

EN2

COMP

22

µH

LX

OUT1

PGND

OUT2

CS

GND

2 TO 4 LEDS

MAIN

DISPLAY

2 TO 3 LEDS

SUB-

DISPLAY

7.5

Ω

ANALOG OR

DIRECT PWM

DIMMING

Typical Application Circuit

MAX1582

1

V+

TOP VIEW

2

VP

3

CTRL

OUT2

CS

EN2

9

8

7

12

11

10

45

6

4mm x 4mm

THIN QFN

Pin Configurations continued at end of data sheet.

*EP = Exposed paddle.

UCSP is a trademark of Maxim Integrated Products, Inc.