General Description
The AAT2805 is a dual charge pump designed to support both the white LED backlight and flash applications for systems operating with lithium-ion/polymer batteries. The backlight charge pump is capable of driving up to four LEDs at a total of 120mA. The current sinks may be operated individually or in parallel for driving higher current LEDs. To maximize power efficiency, the charge pump operates in 1X, 1.5X, or 2X mode, where the mode of operation is automatically selected by comparing the forward voltage of each LED with the input voltage. AnalogicTechs AS2Cwire™ (Advanced Simple Serial Control™) serial digital input is used to enable, disable, and set current for each LED with a 16-level logarithmic scale plus four low-current settings down to 50µA for optimized efficiency, with a typical operating quiescent current of less than 50µA.

FEATUREs
• VIN Range: 2.7V to 5.5V
• Dual Charge Pump to Support Backlight and
   Flash LEDs
• Backlight Charge Pump:
   — Regulated Current
   — Four Current Sink Inputs
   — AS2Cwire Brightness Control
   — Tri-Mode Charge Pump
   — Maximum 30mA of Current Per Input
   — Low IQ (50µA) in Light Load Mode
• Flash Charge Pump:
   — Regulated Output Voltage
   — Up to 250mA of Pulsed Current
• Independent Backlight/Flash Control
• Low Noise 1MHz Constant Frequency
   Operation
• Automatic Soft-Start
• No Inductors
• Available in TDFN44-16 Package

APPLICATIONs
• Color (RGB) Lighting
• White LED Backlighting
• White LED Photo Flash