Rainbow Electronics MAX1554 - Manual

General Description
The MAX1553/MAX1554 drive white LEDs in series with
a constant current to provide efficient display backlight-
ing in cellular phones, PDAs, and other hand-held
devices. The step-up converter includes an internal
40V, low R
DSON , N-channel MOSFET switch for high
efficiency and maximum battery life. The MAX1553 has
a current limit of 480mA for driving two to six white
LEDs, while the MAX1554 has a current limit of 970mA
for driving up to 10 white LEDs.
A single analog/PWM Dual Mode  input provides two
simple means of brightness adjustment. A separate
enable input provides on/off control. Soft-start minimizes
inrush current during startup.
The MAX1553/MAX1554 are available in space-saving
8-pin TDFN 3mm x 3mm packages.
Applications
Cellular Phones
PDA, Palmtop, and Wireless Handhelds
Color Display Backlight
Features
♦ Constant-Current Regulation for Even LED
Illumination
♦ Internal 40V MOSFET Switch Capable of Driving
10 LEDs
♦ Small, Low-Profile External Components
♦ 2.7V to 5.5V Input Range
♦ Up to 88% Efficiency Driving 6 LEDs
♦ Up to 82% Efficiency Driving 9 LEDs
(20mA, V CC = 3.6V)
♦ Analog or PWM Control of LED Intensity
♦ Optimized for Low Input Ripple
♦ Soft-Start to Minimize Inrush Current
♦ 3mm x 3mm 8-Pin TDFN Package
MAX1553/MAX1554
High-Efficiency, 40V Step-Up
Converters for 2 to 10 White LEDs
________________________________________________________________ Maxim Integrated Products 1
TOP VIEW
SS
BRT
6
7
8
0V
LX
3
2
1
EN
V CC
GND
5 FB 4
TDFN
3mm x 3mm
MAX1553
MAX1554
Pin Configuration
Ordering Information
LX
SS
V CC
FB
ON
OFF
BRT
GND
2.7V TO 5.5V
INPUT
OV EN
PWM
OR
DC CONTROL
MAX1553
MAX1554
WHITE
LEDS
Typical Operating Circuit
19-2875; Rev 0; 6/03
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.
EVALUATION KIT
AVAILABLE
PART TEMP RANGE PIN-PACKAGE
MAX1553ETA -40°C to +85°C 8 TDFN 3mm x 3mm
MAX1554ETA -40°C to +85°C 8 TDFN 3mm x 3mm
Dual Mode is a trademark of Maxim Integrated Products, Inc.