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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
Active: In Production.

Data Sheet
FULL DATA SHEET (PDF, 272kB)
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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).

An evaluation kit is available:  MAX8678EVKIT  

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 (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
 
  • 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 Price
max num. of max min max max max See Notes
MAX8678  Charge Pump 4 Parallel Serial Pulse 0.4 244 2.7 5.5 0.2 5 1000
TQFN/16
$1.65 @1k
See All White LED Drivers (47)

Diagram
MAX8678: Typical Operating Circuit
Typical Operating Circuit

Evaluation Kits
  • MAX8678EVKIT
  • Design Guides
  • Amplifiers and Sensors (PDF)
  • Low-Power Notebook ICs (PDF)
  • Audio (PDF)
  • Communications (PDF)
  • Displays (PDF)
  • Flat-Panel Display (PDF)
  • Medical (PDF)
  • Power Management for Battery-Powered Equipment (PDF)
  • Reliability Reports
  • Show FIT data for:
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    Software/Models
    none

    Ordering Information
    Notes:

    1. Other options and links for purchasing parts are listed at: http://www.maxim-ic.com/sales.
    2. Didn't Find What You Need? Ask our applications engineers. Expert assistance in finding parts, usually within one business day.
    3. Part number suffixes: T or T&R = tape and reel;+ = RoHS/lead-free;# = RoHS/lead-exempt. More: SeeFull Data Sheet or Part Naming Conventions.
    4. * Some packages have variations, listed on the drawing. "PkgCode/Variation" tells which variation the product uses. Note that "+", "#", "-" in the part number suffix describes RoHS status. Package drawings may show a different suffix character.


    Devices: 1-2 of 2

    MAX8678 Free
    Sample
    Buy Status
    Package: TYPE PINS FOOTPRINT
      DRAWING CODE/VAR *
    Temp RoHS/Lead-Free?
    Materials Analysis
    MAX8678ETE+  
    Active TQFN;16 pin;9.6 mm²
    Outline Drawing: 21-0136 (PDF)
    Land Pattern: 90-0032 (PDF)
    Use pkgcode/variation: T1633+5*
    -40°C to +85°C RoHS/Lead-Free: Lead Free
    Materials Analysis
    MAX8678ETE+T    
    Active TQFN;16 pin;9.6 mm²
    Outline Drawing: 21-0136 (PDF)
    Land Pattern: 90-0032 (PDF)
    Use pkgcode/variation: T1633+5*
    -40°C to +85°C RoHS/Lead-Free: Lead Free
    Materials Analysis

    More Information
  • Topmark Coding: MAX8678
  • New Product Press Release 2007-05-31 
  • Product Ad: Download

    Related Products
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    MAX1573 White LED 1x/1.5x Charge Pump in UCSP and Thin QFN
    MAX1575 White LED 1x/1.5x Charge Pump for Main and Sub-Displays
    MAX1574 180mA, 1x/2x, White LED Charge Pump in 3mm x 3mm TDFN
    MAX1576 480mA White LED 1x/1.5x/2x Charge Pump for Backlighting and Camera Flash
    MAX1561, MAX1599 High-Efficiency, 26V Step-Up Converters for Two to Six White LEDs
    MAX1578, MAX1579 Complete Bias and White LED Power Supplies for Small TFT Displays
    MAX8595X, MAX8596X High-Efficiency, 36V Step-Up Converters with TA Derating Option for 2 to 9 White LEDs

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


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