Skyworks Solutions Inc. AAT3155ITP-T1

Description
The AAT3155 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. It can drive up to four channels of LEDs at 20mA per channel from a 2.7V to 5.5V input. The current sinks may be operated individually or in parallel for driving higher current LEDs. A low external parts count (two 1uF flying capacitors and two small 1μF capacitors at IN and OUTCP) make this part ideally suited for small, battery-powered applications.
Skyworks' S-Cwire (Simple Serial Control) serial digital input is used to enable, disable, and set current for each LED with 16 settings down to 50μA. The low-current mode supply current can be as low as 50µA to save power.
Each output of the AAT3155 is equipped with built-in protection for output short-circuit and auto-disable for load short-circuit conditions. Built-in soft-start circuitry prevents excessive inrush current during start-up. A low-current shutdown feature disconnects the load from the input and reduces quiescent current to less than 1μA.
The AAT3155 is available in a Pb-free, space-saving 2.85x3.0mm 12-pin TSOPJW package.

Features
VIN Range: 2.7V to 5.5V
Fully Programmable Current with Single Wire
16 Current Levels
Four Low Current Settings Down to 50μA
Low IQ (50μA) for Low Current Mode
Tri-Mode 1X, 1.5X, and 2X Charge Pump for Maximum Efficiency and Vout Coverage
Drives up to Four Channels of LEDs
No Inductors, Low Noise Operation
1MHz Constant Switching Frequency
Small Application Circuit
Built-In Thermal Protection
Automatic Soft Start
Io <1μA in Shutdown
2.85x3.0mm TSOPJW-12 Package

Applications
Color (RGB) Lighting
Programmable Current Sinks
White LED Backlighting
White Photo Flash for Digital Still Cameras