General Description
The AAT3120 is a low noise, constant frequency charge pump DC/DC converter that uses fractional (1.5X) conversion to improve efficiency for white LED applications. The device can be used to produce eight current levels up to 20mA per channel for up to three channels. 1X load switch mode is also built-in to improve efficiency at low current settings. Low external parts count (two 1µF flying capacitors and two small 1µF capacitors at VIN and OUT) makes the AAT3120 ideally suited for small battery-powered applications.

Features
• VIN Range: 2.7V to 5.5V
• Fractional Charge Pump Mode
• Drives Low-VF and High-VF Type LEDs
• Up to Three LED Outputs
    — Single Wire Programming
    — Eight Regulated Current Settings
    — Max 20mA per Channel
• Low Noise Constant Frequency Operation
• No Inductors
• 1MHz Switching Frequency
• Small Application Circuit
• Automatic Soft-Start
• IQ <1µA in Shutdown
• 12-Pin TSOPJW Package

Applications
• Color (RGB) Lighting
• Programmable Current Source
• White LED Backlighting
• White Photo Flash for DSCs