AAT3143

The AAT3143 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 AAT3143 can deliver current levels up to 80mA to connect white LEDs connected to the four current source outputs from a 2.7V to 5.5V input. The current source outputs may source up to 20mA each and 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 V_IN and V_OUT) makes the AAT3143 ideally suited for small battery-powered applications. Output current, and therefore brightness, is controlled via externally applied Pulse Width Modulation (PWM) control. Typically, PWM frequencies of up to 50kHz can be applied. The AAT3143 has a thermal management system to protect the device in the event of a short-circuit condition at the voltage output pin. Built-in soft-start circuitry prevents excessive inrush current during start-up. A high charge pump switching frequency allows the use of very small external capacitors. A low current shutdown feature disconnects the load from V_IN and reduces quiescent current to less than 1A. The AAT3143 is available in a Pb-free, space-saving, 2.85x3.0mm 12-pin TSOPJW package.