MAX8678

White LED Charge Pump with 1.1W Audio Amplifier

Industry’s First LED Charge Pump with Integrated Audio Amplifier Saves 50% PCB Area While Providing Highest Efficiency

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Status Explanations for product status codes

Active: In Production.

Description

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 8Ω 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).

 

Data Sheet

Download this datasheet in PDF formatDownload Rev 0 (PDF, 272kB)
Send this datasheet to any email addressE-Mail
An evaluation kit is available: MAX8678EVKIT

Key Features

  • 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 (8Ω, 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
  • 16-Pin, 3mm x 3mm Thin QFN Package
 

Applications/Uses

  • Camera Phones
  • Cell Phones and Smartphones
  • PDAs, Digital Cameras, Camcorders
   

Key Specifications:

White LED Drivers
Part Number Topology LEDs Config. Dimming Control POUT
(W)
ILED
(mA)
VIN
(V)
VIN
(V)
ICC
(mA)
VOUT
(V)
Oper. Freq.
(kHz)
Package/Pins
max num. of max min max max max
MAX8678  Charge Pump 4 Parallel Serial Pulse 0.4 244 2.7 5.5 0.2 5 1000
TQFN/16
See All White LED Drivers (47)
Pricing 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.


Diagram

MAX8678: Typical Operating Circuit
Typical Operating Circuit

More Information

Topmark Coding MAX8678
New Product Press Release 2007-05-31 ]

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Information Index

Document Ref.: 19-0786 Rev 0; 2007-05-14
This page last modified: 2009-08-19




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