General Description

The MAX8821 integrates a charge pump for white LEDs, an audio loudspeaker amplifier, and two low noise LDOs controlled by an I2C control interface. The high-efficiency, adaptive-mode inverting charge pump drives up to six LEDs with constant current for uniform brightness. The LED current is controlled by an I2C interface and adjusts from 0.1mA to 25.6mA per LED into 32 pseudo-logarithmic steps. Independent voltages for each LED maximize efficiency even with large LED forward voltage (VF) mismatch. An internal temperature derating function reduces the current above +40°C to protect the LEDs.

Features

♦ White LED Inverting Charge Pump

    Independent Adaptive Current Regulators for Each LED

    6 Low-Dropout Current Regulators

    Flexible I2C Dimming Control for Each LED

    Ramp-Up/Down, Current Control for Each LED

    Low 70µA (typ) Quiescent Current

    TA Derating Function Protects LEDs

♦ Mono 2W Class D Loudspeaker Amplifier

    85 Efficiency (RL = 8Ω, POUT = 600mW)

    Low 0.05 THD+N at 1kHz

    High 65dB PSRR at 1kHz

    Fully Differential Inputs

    -3dB to +24dB Gain Settings in 3dB Steps

    Integrated Click-and-Pop Suppression

    Low Quiescent Current

♦ Dual Low-Noise LDO

    45µVRMS Output Noise, 70dB PSRR

    Flexible I2C-Controlled Output Voltages

    200mA and 300mA Output Current Drive

Applications

    Cell Phones and Smartphones

    PDAs, Digital Cameras, Camcorders

    MP3 Players, GPS Devices