Description    

    The AT8808 is a step-down DC/DC converter designed to drive LEDs with a constant current. The device can drive up to 8 LEDs, depending on the forward voltage of the LEDs, in series from a voltage source of 6V to 30V. Series connection of the LEDs provides identical LED currents resulting in uniform brightness and eliminating the need for ballast resistors. The AT8808 switches at frequency up to 1MHz with controlled rise and fall times to reduce EMI. This allows the use of small size external components, hence minimizing the PCB area needed. 

    Maximum output current of AT8808 is set via an external resistor connected between the VIN and SET input pins. Dimming is achieved by applying either an analog DC voltage or a PWM signal at the CTRL input pin. An input voltage of 0.4V or lower at CTRL switches off the output MOSFET simplifying PWM dimming.

Features

    LED Driving Current Up to 1A

    Better Than 5% Accuracy

    High Efficiency Up to 96%

    Fast Controlled Falling Edges 7ns

    Operating Input Voltage from 6V to 30V

    High Switching Frequency Up to 1MHz

    PWM/DC Input for Dimming Control

    Built-In Output Open-Circuit Protection

    Built-In Over-Temperature Protection

    TSOT25: Available in “Green” Molding Compound (No Br, Sb)

Applications

    MR16 Lamps

    General Illumination Lamps

Typical  Circuit