General Description
The MAX8847Y/MAX8847Z negative charge pumps drive up to 6 white LEDs with regulated constant current for display backlight applications. By utilizing an inverting charge pump and extremely low-dropout adaptive current regulators, these ICs achieve very high efficiency over the full 1-cell Li+ battery voltage range even with large LED forward voltage mismatch. The 1MHz fixed-frequency switching allows for tiny external components. The regulation scheme is optimized to ensure low EMI and low input ripple. The MAX8847Y/MAX8847Z include thermal shutdown, open- and short-circuit protection.

FEATUREs
♦ Negative 1x/1.5x Charge Pump
♦ Adaptive Current Regulators
♦ Independent Voltage Supply for Each LED
♦ 24mA to 0.1mA Serial-Pulse Dimming (MAX8847Y)
♦ 24mA to 0mA PWM Dimming (MAX8847Z)
♦ 2% (max) LED Current Accuracy, 1% (typ) Matching
♦ Low 120µA Quiescent Current
♦ Low 0.4µA Shutdown Current
♦ Inrush Current Limit
♦ Temperature Derating Function
♦ 16-Pin, 3mm x 3mm Thin QFN Packages

APPLICATIONs
   White LED Backlighting
   Cellular Phones
   PDAs, Digital Cameras, and Camcorders