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).
Key Features
Applications/Uses
High-Efficiency White LED Charge Pump
Individual Adaptive Supply for Each LED
4 Low-Dropout LED Current Regulators
24mA to 0.1mA Dimming Range
Single-Wire, Serial-Pulse Dimming Interface
1% (typ) Accuracy
Low 140µA Quiescent Current
Mono Class AB Audio Amplifier
1.1W RMS Mono BTL Output (8, VIN = 5V)
Low 0.004% THD+N at 1kHz
High 90dB PSRR at 1kHz
Fully Differential Inputs
-9dB to +18dB Gain Settings in 3dB Steps
Integrated Click/Pop Suppression
Low Quiescent Current
Soft-Start Limits Inrush Current
Thermal Shutdown, Open- and Short-Circuit Protection
Notes: *This pricing is BUDGETARY, for comparing similar parts. Prices are in
U.S. dollars and subject to change. Quantity pricing may vary
substantially and international prices may differ due to local
duties, taxes, fees, and exchange rates. For volume-specific prices
and delivery, please see the price and availability page
or contact an authorized distributor.
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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.