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MAX1576：480mA White LED 1x/1.5x/2x Charge Pump for Backlighting and Camera Flash

The MAX1576 charge pump drives up to 8 white LEDs with regulated constant current for uniform intensity. The main group of LEDs (LED1-LED4) can be driven up to 30mA per LED for backlighting. The flash group of LEDs (LED5-LED8) are independently controlled and can be driven up to 100mA per LED (or 400mA total). By utilizing adaptive 1x/1.5x/2x charge-pump modes and very-low-dropout current regulators, the MAX1576 achieves high efficiency over the full 1-cell lithium-battery voltage range. The 1MHz fixed-frequency switching allows for tiny external components, and the regulation scheme is optimized to ensure low EMI and low input ripple. The MAX1576 uses two external resistors to set the main and flash full-scale (100%) LED currents. Four control pins are used for LED dimming by either serial control or 2-bit logic per group. ENM1 and ENM2 set the main LEDs to 10%, 30%, or 100% of full scale. ENF1 and ENF2 set the flash LEDs to 20%, 40%, or 100% of full scale. In addition, connect either pair of control pins together for single-wire, serial pulse dimming control. The MAX1576 is available in a 24-pin thin QFN, 4mm x 4mm package (0.8mm max height).

Key Features Powers Up to 8 LEDs Up to 30mA/LED Drive for Backlight Up to 400mA Total Drive for Flash 85% Average Efficiency (PLED / PBATT) Over Li+ Battery Discharge 0.7% Typical LED Current Matching Adaptive 1x/1.5x/2x Mode Switchover Flexible Brightness Control Single-Wire, Serial Pulse Interface (5% to 100%) 2-Bit (3 Levels) Logarithmic Logic Low Input Ripple and EMI Low 0.1µA Shutdown Current 2.7V to 5.5V Supply Voltage Range Soft-Start Limits Inrush Current Output Overvoltage Protection Thermal-Shutdown Protection 24-Pin Thin QFN, 4mm x 4mm Package

MAX1576: Typical Application Circuit Applications/Uses Camera Phones Cell Phones/Smartphones LCD Backlights LED Camera Flashes PDAs, Digital Cameras, and Camcorders

DataSheet

Parametrics

Design kits & evaluation modules

• MAX1576EVKIT

Quality and Environmental Data

• MAX1576.pdf

Related Products

• MAX1575：White LED 1x/1.5x Charge Pump for Main and Sub-Displays
• MAX1582：High-Efficiency Step-Up Converters for White LED Main and Subdisplay Backlighting

Ordering Information