19-2731; Rev 1; 10/03
KIT
ATION
EVALU
E
AILABL
AV
High-Efficiency, 26V Step-Up Converters
for Two to Six White LEDs
The MAX1561/MAX1599 step-up converters drive up to
six white LEDs with a constant current to provide backlight in cell phones, PDAs, and other hand-held
devices. The step-up converter topology allows series
connection of the white LEDs so the LED currents are
identical for uniform brightness. This configuration eliminates the need for ballast resistors and expensive factory calibration.
The MAX1561/MAX1599 include an internal, high-voltage, low-RDS(ON) N-channel MOSFET switch for high
efficiency and maximum battery life. A single Dual
Mode™ input provides a simple means of brightness
adjustment and on/off control. Fast 1MHz (500kHz for
the MAX1599) current-mode, pulse-width modulated
(PWM) operation allows for small input and output
capacitors and a small inductor while minimizing ripple
on the input supply/battery. Programmable soft-start
eliminates inrush current during startup.
Features
♦ Accurate Current Regulation for Uniform
Illumination
♦ High Efficiency Up to 87%
♦ Flexible Analog or PWM Dimming Control
♦ Up to 900mW Output Power with Internal 30V
MOSFET Switch
♦ Fast 1MHz (MAX1561) or 500kHz (MAX1599) PWM
Operation
♦ Small, Low-Profile External Components
♦ 2.6V to 5.5V Input Range
♦ 26V (max) Output with Overvoltage Protection
♦ Optimized for Low 15mVP-P Input Ripple
♦ Soft-Start with Zero Inrush Current
♦ 0.3µA Shutdown Current
♦ Tiny 8-Pin 3mm x 3mm Thin DFN Package
Both devices are available in a space-saving, 8-pin 3mm
x 3mm thin DFN package with exposed paddle (EP).
Ordering Information
Applications
TOP
MARK
PART
TEMP RANGE
PIN-PACKAGE
PDAs, Palmtops, and Wireless Handhelds
MAX1561ETA
-40°C to +85°C
8 TDFN-EP*
ACS
e-Books and Subnotebooks
MAX1599ETA
-40°C to +85°C
8 TDFN-EP*
AHG
Cell Phones and Smart Phones
White LED Display Backlighting
*EP = Exposed paddle.
Pin Configuration
Typical Operating Circuit
INPUT 2.6V TO 5.5V
OUTPUT UP TO 6 LEDs
TOP VIEW
LX
IN
MAX1561
MAX1599
OUT
OUT 1
PWM OR
ANALOG
DIMMING
MAX1561
MAX1599
7 PGND
6 GND
CTRL 3
CTRL
PGND
COMP
CS
GND
8 LX
IN 2
5 COMP
CS 4
3mm × 3mm
THIN DFN
Dual Mode is a trademark of Maxim Integrated Products, Inc.
________________________________________________________________ Maxim Integrated Products
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.
1
MAX1561/MAX1599
General Description