General Description
The MAX8901A/MAX8901B step-up converters drive from two to six series-connected white LEDs (WLEDs) with constant current to provide uniform WLED intensity for LCD backlighting in cell phones, PDAs, and other handheld devices. The MAX8901_ operate at a fixed 750kHz (typ) switching frequency, allowing for tiny external components, and are optimized for the highest possible efficiency over the full 1-cell Li+/Li-Poly battery range.
Benefits and Features
• Cost-Effective and Flexible Solution for Wide Range of Backlighting Applications
• Supplies from 2 to 6 WLEDs with 1.3% LED Current Accuracy
• 2.6V to 5.5V Input Voltage Range
• Fixed-Frequency Operation
• Flexible Dimming Control
• Direct PWM Dimming (MAX8901A)
• 32-Step, Single-Wire Serial Dimming (MAX8901B)
• Protection Features Improve System Reliability
• WLED Overvoltage Protection (25V typ)
• Internal Soft-Start and Thermal Shutdown
• Input Undervoltage Lockout
• Input Overvoltage Lockout
• High Efficiency Extends Battery Life
• Up to 91% Efficiency
• 0.01µA (typ) Shutdown Current
• No WLED Current in Shutdown
• 8-Pin, 2mm x 2mm TDFN Package Saves Space
APPLICATIONs
Display Backlight (from 2 to 6 WLEDs)
Cellular Phones
PDAs and Smartphones
MP3 and Portable Media Players
Portable Navigation Devices
Digital Cameras