MAX1553 Datasheet, PDF (1/11 Pages) Maxim Integrated Products – High-Efficiency, 40V Step-Up Converters for 2 to 10 White LEDs

19-2875; Rev 0; 6/03
EVAALVUAAILTAIOBNLEKIT
High-Efficiency, 40V Step-Up
Converters for 2 to 10 White LEDs
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.
Features
o Constant-Current Regulation for Even LED
Illumination
o Internal 40V MOSFET Switch Capable of Driving
10 LEDs
o Small, Low-Profile External Components
o 2.7V to 5.5V Input Range
o Up to 88% Efficiency Driving 6 LEDs
o Up to 82% Efficiency Driving 9 LEDs
(20mA, V_CC = 3.6V)
o Analog or PWM Control of LED Intensity
o Optimized for Low Input Ripple
o Soft-Start to Minimize Inrush Current
o 3mm x 3mm 8-Pin TDFN Package
Applications
Cellular Phones
PDA, Palmtop, and Wireless Handhelds
Color Display Backlight
PART
MAX1553ETA
MAX1554ETA
Ordering Information
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
8 TDFN 3mm x 3mm
8 TDFN 3mm x 3mm
Dual Mode is a trademark of Maxim Integrated Products, Inc.
Typical Operating Circuit
2.7V TO 5.5V
INPUT
ON
OFF
PWM
OR
DC CONTROL
V_CC
LX
EN
OV
MAX1553
MAX1554
BRT
FB
SS
GND
WHITE
LEDS
TOP VIEW
Pin Configuration
GND 1
V_CC 2
EN 3
BRT 4
MAX1553
MAX1554
8 LX
7 0V
6 SS
5 FB
TDFN
3mm x 3mm
________________________________________________________________ Maxim Integrated Products 1
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.