AAT3157

The AAT3157 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 AAT3157 is capable of driving up to three 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 1F flying capacitors and two small 1F capacitors at IN and OUTCP) 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 50A. The low-current mode supply current can be as low as 50A to save power. Each output of the AAT3157 is equipped with builtin protection for output short-circuit and auto-disable for load short-circuit conditions.

Built-in softstart 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 1A. The AAT3157 is available in a Pb-free, space-saving 2.85x3.0mm 12-pin TSOPJW package.