National Semiconductor | High-performance Analog

 

 LM2796   
Dual-Display White LED Driver with 3/2x Switched Capacitor Boost from the PowerWise® Family		 Click link to Download

Features
  • Drives up to 7 LEDs with up to 20mA each
  • LEDs controlled in 2 Distinct Groups, for Backlighting 2 Displays (main LCD and sub-LCD)
  • Excellent Current and Brightness Matching
  • High-Efficiency 3/2x Charge Pump
  • Extended Li-Ion Input: 2.7V to 5.5V
  • PWM Brightness Control: 100Hz - 1kHz
  • 18-bump Thin Micro SMD Package: (2.1mm x 2.4mm x 0.6mm)

    • Description

    The LM2796 is a charge-pump based white-LED driver that is ideal for mobile phone display backlighting. It can drive up to 7 LEDs in parallel with up to 20mA through each LED. Regulated internal current sources deliver excellent current and brightness matching in all LEDs. The LED-driver current sources are split into two independently controlled groups. The primary group (4 LEDs) can be used to backlight the main phone display. The second group (3 LEDs) can be used to backlight a secondary display or to provide other lighting features (keypad LEDs, for example). Brightness of the two groups can be adjusted independently with pulse-width modulated (PWM) digital signals.

    The LM2796 works off an extended Li-Ion input voltage range (2.7V to 5.5V). Voltage boost is achieved with a high-efficiency 3/2×-gain charge pump.

    The LM2796 is available in National's chip-scale 18-bump micro SMD package.


    Applications

  • Mobile Phone Display Lighting
  • Mobile Phone Keypad Lighting
  • PDAs
  • General LED Lighting

    • Also Recommended
    LP39366 White LED And 1 RGB Drivers With Inductive Boost
    LM2793▲2 LED Outputs, LLP
    LM2794▲4 LED Outputs With Active-Low Shutdown Pin
    LM2795▲4 LED Outputs With Active-High Shutdown Pin
    LP39336 White LED And 2 RGB Drivers With Inductive Boost



    Typical Application
    click for larger image


    		Connection Diagram
    click for larger image



    Typical Performance
    click for larger image


    Parameters / ValuesLM2796 LM2793 LM2794 LM2795
    Regulated LEDs7 4 4
    Total LED Current140 mA 80 mA 80 mA
    Current Matching1% 0.5% 0.5%
    Boost TypeSwitched Capacitor 1.5x Switched Capacitor 1.5x Switched Capacitor 1.5x
    Switching Frequency500 kHz 515 kHz 515 kHz
    Efficiency (peak)80 % 80 % 80 %
    Input Min Voltage2.7 Volt 2.7 Volt 2.7 Volt
    Input Max Voltage5.5 Volt 5.5 Volt 5.5 Volt
    Boost VoltageUnregulated Unregulated Unregulated
    LED ConfigurationParallel Parallel Parallel
    Supply Current3.5 mA 5.5 mA 5.5 mA
    Switching TypeFixed Freq Fixed Freq Fixed Freq
    Special FeaturesLEDs controlled in 2 groups: 3 and 4 LEDs; softstart Active low shutdown Active high shutdown
    PWM BrightCtrlYes Yes Yes
    Analog-V BrightCtrlNo Yes Yes
    Ambient Light CompensationNo No No
    RGB-LEDNo No No
    Temperature Min-30 deg C -30 deg C -30 deg C
    Temperature Max85 deg C 85 deg C 85 deg C
    RegTypeWhiteLED Driver WhiteLED Driver WhiteLED Driver
    PowerWiseYes No No

    Datasheets
    TitleSizeDateOther
    Language
    LM2796 Dual-Display White LED Driver with 3/2x Switched Capacitor Boost172
    Kbytes    		25-Feb-04   


    Application Notes
    TitleSizeDateOther
    Language
    AN-1321: Application Note 1321 LM2796 Evaluation Board453
    Kbytes    		25-May-04 

    Part Number(s)
    (NSID)    		Top ViewAvailabilityCurrent Reported StockBudgetary PricingPack
    Size
    LM2796TL/NOPB


    RoHS Status

    MICRO SMD    		Full production
    Lead Time: 6 weeks

    Samples
    DistributorRegionQty
    DIGI-KEYWorldwide0
    RS COMPONENTSWorldwide243
    		$0.95 each at 1K+ pcsreel
    of
    250
    LM2796TLX/NOPB


    RoHS Status

    MICRO SMD    		Full production
    Lead Time: 6 weeks

     
    DistributorRegionQty
    DIGI-KEYWorldwide0
    		$0.95 each at 1K+ pcsreel
    of
    3000

    All information pertaining to the RoHS Compliance Standard can be found at http://www.national.com/en/packaging/leadfree.html.

    Moisture Sensitivity Level Data for LM2796.

    A RoHS compliance or an IPC 1752 report can be acquired at http://www.national.com/en/packaging/greennopb.html.

    National's certificate of product compliance for LM2796 is located at RoHS Status.

    Part Number(s)
    (NSID)    		DescriptionAvailabilityCurrent Reported StockBudgetary PricingPack
    Size
    LM2796TLEV
    		Dual-Display White LED Driver with 3/2x Switched Capacitor BoostFull production


     
    DistributorRegionQty
    DIGI-KEYWorldwide0
    FARNELLEurope and Asia3
    NEWARKAmericas3
    		$79.00 each1

    Description:

    The LM2796 is a charge-pump based white-LED driver that is ideal for mobile phone display backlighting.

    Features:

    • Drives up to 7 LEDs withup to 20mA each
    • LEDs controlled in 2 Distinct Groups, for Backlighting 2 Displays (main LCD and sub-LCD)
    • Excellent Current and Brightness Matching
    • High-Efficiency 3/2x Charge Pump
    • Extended Li-Ion Input: 2.7V to 5.5V
    • PWM Brightness Control: 100Hz - 1kHz
    • 18-bump Thin Micro SMD Package:
        (2.1mm x 2.4mm x 0.6mm)

    Applications:

    • Mobile Phone Display Lighting
    • Mobile Phone Keypad Lighting
    • PDAs
    • General LED Lighting



    National Semiconductor follows the provisions of the Product Stewardship Guide for Customers (CSP-9-111C1) and Banned Substances and Materials of Interest Specification (CSP-9-111S2) for regulatory environmental compliance. Details may be found at: www.national.com/en/packaging/greennopb.html. Lead free products are RoHS compliant.

    Lead Free product status is available through the search tool located here

    Part Number(s)
    (NSID)    		Weight
    (milligrams)    		TypePinsMSL RatingPeak ReflowRoHS
    Status    		CAD SymbolsModelsPackage
    Marking
    Format
    LM2796TL/NOPB

    		6.218
    		MICRO SMD181260DetailDownloadN/A
    		XYTT
    I SAJB
    LM2796TLX/NOPB

    		6.218
    		MICRO SMD181260DetailDownloadN/A
    		XYTT
    I SAJB

    All information pertaining to the RoHS Compliance Standard can be found at http://www.national.com/en/packaging/leadfree.html.

    Moisture Sensitivity Level Data for LM2796.

    A RoHS compliance or an IPC 1752 report can be acquired at http://www.national.com/en/packaging/greennopb.html.

    National's certificate of product compliance for LM2796 is located at RoHS Status.

    CAD Symbols and Models
    Download LM2796 CAD Symbols
    		 Models
    N/A


    Reliability Metrics
    Part Number Process EFR Reject EFR Sample Size PPM LTA Rejects LTA Device Hours FITS MTTF (Hours)
    LM2796TLCS065247473430552700011568301341
    LM2796TLXCS065247473430552700011568301341

    Note: The Early Failure Rates (EFR) were calculated as point estimate PPM based on rejects and sample size for EFR. The Long Term Failure Rates were calculated at 60% confidence using the Arrhenius equation at 0.7eV activation energy and derating the assumed stress temperature of 150°C to an application temperature of 55°C.

    For more information on Reliability Metrics, please click here.


    All information pertaining to the RoHS Compliance Standard can be found at http://www.national.com/en/packaging/leadfree.html.

    Moisture Sensitivity Level Data for LM2796.

    A RoHS compliance or an IPC 1752 report can be acquired at http://www.national.com/en/packaging/greennopb.html.

    National's certificate of product compliance for LM2796 is located at RoHS Status.

    [Information as of 9-Feb-2012]
    Copyright © 2011 National Semiconductor Corporation