General Description

The MAX8631X/Y charge pump drives up to eight white LEDs with regulated constant current for uniform intensity. The main group of LEDs (M1–M4) can be driven up to 30mA per LED for backlighting. The flash group of LEDs (F1–F4) is independently controlled and can be driven up to 100mA per LED (or 400mA total). Two 200mA LDOs are on-board to provide power for camera functions. The LDOs’ output voltages are pin-programmable to meet different camera-module requirements. By utilizing adaptive 1x/1.5x/2x charge-pump modes and very-low-dropout current regulators, the MAX8631X/Y 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.

特性 Features

? Powers Up to 8 LEDs

?? Up to 30mA/LED Drive for Backlight

?? Up to 400mA Total Drive for Flash

? Two Internal Low-Noise 200mA LDOs

? 94 Max/85 Avg Efficiency (PLED/PBATT) over Li+ Battery Discharge

? 0.2 Typical LED Current Matching

? Adaptive 1x/1.5x/2x Mode Switchover

? Single-Wire Serial Pulse Interface for Brightness Control (32 Steps)

? Thermal TA Derating Function

? Low Input Ripple and EMI

? 2.7V to 5.5V Supply Voltage Range

? Soft-Start, Overvoltage, and Thermal-Shutdown Protection

? 28-Pin Thin QFN, 4mm x 4mm Package

Applications

?? Camera Phones and Smartphones

?? Backlighting and Flash

?? PDAs, Digital Cameras, and Camcorders