General Description

The MAX1698 is the most efficient driver for white or

color LEDs. The device is ideal for LED backlit displays

in PDAs and digital cameras, and can also be used for

larger displays like those in laptop computers. Its

numerous benefits include greater simplicity, lower

cost, higher efficiency, longer bulb life, and greater reli-

ability when compared to fluorescent (CCFL) and elec-

troluminescent (EL) lamps.

The MAX1698 is a switch-mode boost controller in

which LED current, rather than output voltage, provides

the feedback signal. It can operate with battery inputs

as low as 0.8V. The device drives series-connected

LEDs with a controlled current that is measured at a

sense resistor connected at the feedback pin. The

required sense resistor is typically 15

Ω, not an expen-

sive fractional-ohm value. LED current control and dim-

ming are accomplished with an adjust input (ADJ), not

with lossy current-limiting resistors. For larger light out-

put, multiple LED banks can be connected in parallel

with up to 5W total output power.

The MAX1698 is supplied in a space-saving 10-pin

µMAX package that occupies half the space of an 8-pin

SO. An evaluation kit (MAX1698EVKIT) is available to

speed designs.

Applications

Battery-Powered Backlight Applications

Backlight for LCD Panels

Cell Phones

Handy Terminals

PDAs

Features

o Over 90% Efficiency

o Lossless, Adjustable LED Brightness

o Space-Saving 10-Pin µMAX Package

o Simpler, Lower Cost, More Reliable Compared

to CCFL or EL Backlights

o Up to 5W Output Power

High-Efficiency Step-Up

Current Regulator for LEDs

________________________________________________________________ Maxim Integrated Products

1

1

2

3

4

5

10

9

8

7

6

EXT

CS

PGND

GND

ADJ

REF

MAX1698

µMAX

TOP VIEW

FB

GND

SHDN

SHDN

FB

GND

ADJ

REF

CS

ON

OFF

PGND

EXT

D1

MAX1698

L

Typical Operating Circuit

19-1621; Rev 0; 1/00

PART

MAX1698EUB

-40°C to +85°C

TEMP. RANGE

PIN-PACKAGE

10 µMAX

EVALUATION

KIT

AVAILABLE

Pin Configuration

Ordering Information

For free samples and the latest literature, visit www.maxim-ic.com or phone 1-800-998-8800.

For small orders, phone 1-800-835-8769.