MAX1561 Datasheet, PDF (1/10 Pages) Maxim Integrated Products – High-Efficiency, 26V Step-Up Converters for Two to Six White LEDs

19-2731; Rev 1; 10/03
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High-Efficiency, 26V Step-Up Converters
for Two to Six White LEDs
General Description
The MAX1561/MAX1599 step-up converters drive up to
six white LEDs with a constant current to provide back-
light 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 elim-
inates the need for ballast resistors and expensive fac-
tory calibration.
The MAX1561/MAX1599 include an internal, high-volt-
age, low-R_DS(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.
Both devices are available in a space-saving, 8-pin 3mm
x 3mm thin DFN package with exposed paddle (EP).
Applications
Cell Phones and Smart Phones
PDAs, Palmtops, and Wireless Handhelds
e-Books and Subnotebooks
White LED Display Backlighting
Typical Operating Circuit
Features
o Accurate Current Regulation for Uniform
Illumination
o High Efficiency Up to 87%
o Flexible Analog or PWM Dimming Control
o Up to 900mW Output Power with Internal 30V
MOSFET Switch
o Fast 1MHz (MAX1561) or 500kHz (MAX1599) PWM
Operation
o Small, Low-Profile External Components
o 2.6V to 5.5V Input Range
o 26V (max) Output with Overvoltage Protection
o Optimized for Low 15mV_P-P Input Ripple
o Soft-Start with Zero Inrush Current
o 0.3µA Shutdown Current
o Tiny 8-Pin 3mm x 3mm Thin DFN Package
Ordering Information
PART
TEMP RANGE PIN-PACKAGE
MAX1561ETA -40°C to +85°C 8 TDFN-EP*
MAX1599ETA -40°C to +85°C 8 TDFN-EP*
*EP = Exposed paddle.
TOP
MARK
ACS
AHG
Pin Configuration
INPUT 2.6V TO 5.5V
PWM OR
ANALOG
DIMMING
IN
LX
OUT
MAX1561
MAX1599
CTRL
PGND
COMP
CS
GND
OUTPUT UP TO 6 LEDs
TOP VIEW
MAX1561
MAX1599
OUT 1
IN 2
CTRL 3
CS 4
8 LX
7 PGND
6 GND
5 COMP
3mm × 3mm
THIN DFN
Dual Mode is a trademark of Maxim Integrated Products, Inc.
________________________________________________________________ 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.