General Description

The AAT3131 is a low noise, constant frequency charge pump DC/DC converter that uses a dual mode load switch (1X) and fractional (1.5X) conversion to maximize efficiency for white LED applications. The device can be used to produce current levels up to 20mA in three of its outputs and 30mA in one of its outputs to drive LEDs from a 2.7V to 5.5V input. Outputs may be operated individually or paralleled for driving higher-current LEDs. A low external parts count (two 1µF flying capacitors and two small 1µF capacitors at VIN and OUT) makes the AAT3131 ideally suited for small battery-powered applications.

Features

• VIN Range: 2.7V to 5.5V

• <1.0µA of Shutdown Current

• 1MHz Switching Frequency

• White LED Backlighting

• Fully Independent Display Lighting

• Dual Mode 1X and 1.5X Charge Pump for Maximum Efficiency

• Drives Low-VF and High-VF Type LEDs

• Up to Three 20mA Outputs

• Single 30mA Output

• Multi-Position Logarithmic Scale with Digital Control

• Low Noise Constant Frequency Operation

• Regulated Output Current

• Automatic Soft Start

• No Inductors

• Temperature Range: -40°C to +85°C

• 12-Pin TSOPJW Package

Applications

• Color (RGB) Lighting

• Programmable Current Source

• White LED Backlighting

• White Photo Flash for Digital Still Cameras