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