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ADM8843:  Four White LED Backlight Driver

The ADM8843 uses charge pump technology to provide the power to drive up to four LEDs. The LEDs are used for back-lighting a color LCD display that has regulated constant current for uniform brightness intensity. The main display can use up to three LEDs, and the sub display uses one LED. The CTRL1 and CTRL2 digital input control pins control the shutdown opera-tion and the brightness of the ...More

ADM8843:  Four White LED Backlight Driver

Product Description

The ADM8843 uses charge pump technology to provide the power to drive up to four LEDs. The LEDs are used for back-lighting a color LCD display that has regulated constant current for uniform brightness intensity. The main display can use up to three LEDs, and the sub display uses one LED. The CTRL1 and CTRL2 digital input control pins control the shutdown opera-tion and the brightness of the main and sub displays.

To maximize power efficiency, the charge pump can operate in 1×, 1.5×, or 2× mode. The charge pump automatically switches among 1×/1.5×/2× modes, based on the input voltage, to maintain sufficient drive for the LED anodes at the highest power efficiency.

Improved brightness matching of the LEDs is achieved by a feedback pin that senses individual LED current with a typical matching accuracy of 0.3%.

Applications

  • Cellular phones with main and sub displays
  • White LED backlighting
  • Camera flash/strobes and movie light applications
  • Micro TFT color displays
  • DSC
  • PDAs
  • Data Sheet, Rev. A, 12/06

    Eb

    EVALUATION BOARDS & DEVELOPMENT KITS

    • Drives 4 LEDs from a 2.6 V to 5.5 V (Li-Ion) input supply
    • 1×/1.5×/2× fractional charge pump to maximize power efficiency
    • Up to 88% power efficiency over Li-Ion range
    • Powers main and sub display LEDs with individual shutdown
    • 0.3% typical LED current matching
    • Package footprint only 9 mm2 (3 mm × 3 mm)
    • Package height only 0.55 mm
    • Low power shutdown mode
    • Shutdown function
    • Soft start limiting in-rush current
    • Product Description: 4 White LED Backlight Driver for LCD Backlight
    • Input Voltage Range (Vcc): 2.6 to 5.5V
    • Base Drive (mA): n/a
    • Efficency (%): 88%
    • LED #: 4
    • Frequency Range : 0.1 to 200 kHZ
    • Package: 16-LFCSP

    Functional Block Diagram for ADM8843

    OF NOTE...

    Part# Input Voltage Range (Vcc) Vout Adjust Options Iout (max) (mA) Switching Frequency (MHz) Package Price* (1000-4999)
    ADM8843 2.6 to 5.5V - 20 1.5 16-LFCSP $0.50
    ADM8845 2.6 to 5.5V - 30 - 16-LFCSP $0.71
    ADP1610 2.5 to 5.5 V Vin to 12 V 1.2 1.2 8-MSOP $1.12
    ADP1611 2.5 to 5.5 V Vin to 20 V 1.2 1.2 8-MSOP -
    ADP1653 2.75 to 5.5 V - 500 1.2 16-LFCSP $1.45
    ADP1655 2.75 to 5.5 V - 500 2 12-WLCSP $0.95
    ADP5520 2.27 to 5.5 V - 30 1 - $1.66

    * The pricing listed here is provided only for budgetary purposes as recommended list price in U.S. Dollars in the United States ex factor per unit for the stated volume. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.
    ** Pricing is currently unavailable. Click on the product number to see the Product Page for additional information.

    Pricing, Packaging & Availability

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    *The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.
    **Sample availability may be better than production availability. Please enter samples into your cart to check sample availability.