The MAX8678 integrates a charge pump for white light-emitting
diodes (LEDs) with an audio loudspeaker
amplifier. The high-efficiency, adaptive charge pump
drives up to four LEDs with constant current for uniform
brightness. The LED current is adjustable from
0.1mA/LED to 24mA/LED in 31 pseudo-logarithmic
steps through a single-wire serial-pulse interface. High
accuracy and LED-to-LED current matching are maintained
throughout the adjustment range. Individual
adaptive mode switching for each LED provides high
efficiency with a wide range of LED forward voltages.
The mono class AB audio amplifier directly drives an 8 loudspeaker with 1.1W RMS continuous power from a 5V
supply with less than 1% THD+N. The gain is adjustable
from -9dB to +18dB in ten 3dB steps through a single-wire
serial-pulse interface. Clicks and pops are suppressed
during on/off and all gain adjustments.
Differential inputs improve common-mode noise rejection.
The MAX8678 includes soft-start, thermal shutdown,
open-circuit and short-circuit protection, and is available
in the 16-pin, 3mm x 3mm Thin QFN package
(0.8mm max height).
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loudspeaker with 1.1W RMS continuous power from a 5V
supply with less than 1% THD+N. The gain is adjustable
from -9dB to +18dB in ten 3dB steps through a single-wire
serial-pulse interface. Clicks and pops are suppressed
during on/off and all gain adjustments.
Differential inputs improve common-mode noise rejection.