19-2783; Rev 0; 4/03
High-Efficiency, 26V Step-Up Converter
for White LED Main and Subdisplay Backlighting
General Description
Features
ꢀ Accurate Current Regulation for Uniform
The MAX1582 drives up to six white LEDs in series with
a constant current to provide display backlighting for
two (main and sub-) displays in cell phones and other
hand-held devices. This configuration eliminates the
need for ballast resistors and expensive factory calibra-
tion. The proprietary dual-output, step-up pulse-width
Illumination
ꢀ Lights Up Two LED Sections for Main and
Subdisplays
ꢀ Up to 84% Efficiency
ꢀ Internal High-Power, 30V MOSFET
modulation (PWM) converter includes a 30V, low R
DSON
N-channel MOSFET switch for high efficiency and maxi-
mum battery life.
ꢀ Low 15mV
Input Ripple
P-P
ꢀ Flexible Dimming Control
The MAX1582 utilizes 1MHz current-mode PWM control
to allow small input and output capacitors and a small
inductor, while minimizing ripple on the input supply and
avoiding interference to sensitive circuitry in the equip-
ment. Integrated overvoltage protection eliminates the
need for an external zener diode to protect the IC from
open circuit. Flexible dimming control utilizes either an
analog control signal or direct digital PWM control with-
out external RC filtering. This also increases dimming
accuracy at low brightness levels. The PWM dimming
signal can be any frequency from 200Hz to 200kHz.
Soft-start eliminates inrush current during startup.
Analog DAC Controlled
Direct-Digital PWM (No RC Required)
from 200Hz to 200kHz
ꢀ Overvoltage Protection to Eliminate Zener Diode
ꢀ Constant 1MHz PWM Operation
ꢀ Low-Profile Inductor and Capacitors
ꢀ Soft-Start Eliminates Inrush Current
ꢀ 2.6V to 5.5V Input
ꢀ 0.01µA (typ) Shutdown Current
ꢀ Tiny UCSP (2.1mm ✕ 2.1mm ✕ 0.61mm) and Thin
QFN (4mm ✕ 4mm) Packages
The MAX1582 is available in tiny 4 ✕ 4 chip-scale
(UCSP™) and 12-pin thin QFN packages.
Applications
Ordering Information
Cell Phones with One or Two Displays
TOP
MARK
PART
TEMP RANGE PIN-PACKAGE
Smart Phones, Palmtops, and Wireless
Handhelds
MAX1582ETC -40°C to +85°C 12 Thin QFN-EP*
MAX1582EBE-T -40°C to +85°C 16 UCSP-16
*EP = Exposed paddle.
AACE
1582EBE
Other Hand-Held Devices with Dual Displays
Typical Application Circuit
UCSP is a trademark of Maxim Integrated Products, Inc.
Pin Configurations
INPUT
2.6V TO 5.5V
22µH
TOP VIEW
2.2µF
V+
VP
LX
12 11 10
MAX1582
0.1µF
OUT1
ANALOG OR
DIRECT PWM
DIMMING
MAIN
DISPLAY
2 TO 4 LEDS
CTRL
V+
VP
1
2
3
9
8
7
OUT2
CS
PGND
OUT2
MAX1582
EN1
CTRL
EN2
SUB-
DISPLAY
2 TO 3 LEDS
EN2
4
5
6
COMP
CS
0.022µF
4mm x 4mm
THIN QFN
7.5Ω
GND
Pin Configurations continued at end of data sheet.
________________________________________________________________ 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.