AAT3158

AAT3158 High Efficiency 1X/1.5X/2X Charge Pump for White LED Applications General Description The AAT3158 is a low noise, constant frequency charge pump DC/DC converter that uses a trimode load switch (1X), fractional (1.5X), and doubling (2X) conversion to maximize efficiency for white LED applications. The AAT3158 is capable of driving up to four LED channels 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 1µF flying capacitors and two small 1µF capacitors at VIN and VOUT) make this part ideally suited for small, battery-powered applications. AnalogicTech's S2Cwire™ (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 AAT3158 is equipped with builtin protection for VOUT 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 VIN and reduces quiescent current to less than 1µA. The AAT3158 is available in a Pb-free, space-saving 2.85x3.0mm TSOPJW-12 package. Features • • • • • • • • • • • • ChargePump™ 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 VF Coverage Drives Up to Four LED Channels No Inductors, Low Noise Operation 1MHz Constant Switching Frequency Small Application Circuit Built-In Thermal Protection Automatic Soft-Start IQ