MAX1582

Features:

 Accurate Current Regulation for Uniform
  Illumination
 Lights Up Two LED Sections for Main and
  Subdisplays
 Up to 84% Efficiency
 Internal High-Power, 30V MOSFET
 Low 15mVP-P Input Ripple
 Flexible Dimming Control
   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


Application

Cell Phones with One or Two Displays
Smart Phones, Palmtops, and Wireless
Handhelds
Other Hand-Held Devices with Dual Displays


Pinout




Specifications

V+, VP, CTRL to GND............................................-0.3V to +6.0V
PGND to GND .......................................................-0.3V to +0.3V
LX, OUT1 to GND...................................................-0.3V to +30V
OUT2 to GND .........................................................-0.3V to +14V
COMP, CS, EN1, EN2 to GND....................-0.3V to (VV+ + 0.3V)
ILX ....................................................................................................1ARMS
Continuous Power Dissipation (TA = +70°C)
12-Pin Thin QFN (derate 16.9mW/°C above +70°C) ....1349mW
16-Pin UCSP (derate 6.5mW/°C above +70°C)..............518mW
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C


Description

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 modulation (PWM) converter includes a 30V, low RDSON N-channel MOSFET switch for high efficiency and maxi- mum battery life.
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.
The MAX1582 is available in tiny 4 ✕ 4 chip-scale (UCSP™) and 12-pin thin QFN packages.