General Description
The AAT3140 is a low noise, constant frequency charge pump DC/DC converter that uses a tri-mode load switch (1X), fractional (1.5X), and doubling (2X) conversion to maximize efficiency for white LED applications. The device produces current levels up to 30mA on each of its four current source outputs to drive various arrangements of LEDs from a 2.7V to 5.5V input. Outputs may be operated individually or in parallel for driving higher-current LEDs. A low external parts count (two 1µF flying capacitors and two small 1µF capacitors at VIN and CP) make the AAT3140 ideally suited for small battery-powered applications.

FEATUREs
• VIN Range: 2.7V to 5.5V
• Tri-Mode 1X, 1.5X, and 2X Charge Pump for Maximum Efficiency and VF Coverage
• Drives Low-VF and High-VF Type LEDs
• Up to Four 30mA Outputs
• 32-Position Logarithmic Scale with Digital Control
• Low Noise Constant Frequency Operation
• 1MHz Switching Frequency
• AutoBias Technology
• Small Application Circuit
• Regulated Output Current
• Automatic Soft Start
• No Inductors
• IQ < 1µA in Shutdown
• 12-Pin TSOPJW Package

APPLICATIONs
• Color (RGB) Lighting
• Programmable Current Sources
• White LED Backlighting
• White Photo Flash for Digital Still Cameras