National Semiconductor | High-performance Analog

 

 LM27964   
White LED Driver System with I2C Compatible Brightness Control 		Click link to Download

Features

  • 87% Peak LED Drive Efficiency
  • 0.2% Current Matching between Current Sinks
  • Drives 6 LEDs with up to 30mA per LED in two distinct groups, for backlighting two displays (main LCD and sub LCD)
  • Dedicated Keypad LED Driver with up to 80mA of drive current
  • Independent Resistor-Programmable Current Settings
  • I 2C Compatible Brightness Control Interface
  • Adaptive 1×- 3/2× Charge Pump
  • Extended Li-Ion Input: 2.7V to 5.5V
  • Small low profile industry standard leadless package, LLP 24 : (4mm x 4mm x 0.8mm)
  • LM27964SQ-I LED PWM frequency = 10kHz, LM27964SQ-C LED PWM frequency = 23kHz

    • Description

    The LM27964 is a charge-pump-based white-LED driver that is ideal for mobile phone display backlighting. The LM27964 can drive up to 6 LEDs in parallel along with multiple keypad LEDs, with a total output current up to 180mA. Regulated internal current sources deliver excellent current 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 and the second group (2 LEDs) can be used to backlight a secondary display. A single Keypad LED driver can power up to 16 keypad LEDs with a current of 5mA each. The LM27964 has an I 2C compatible interface that allows the user to independently control the brightness on each bank of LEDs.

    The LM27964 works off an extended Li-Ion input voltage range (2.7V to 5.5V). The device provides excellent efficiency without the use of an inductor by operating the charge pump in a gain of 3/2, or in Pass-Mode. The proper gain for maintaining current regulation is chosen, based on LED forward voltage, so that efficiency is maximized over the input voltage range.

    The LM27964 is available in National's small 24-pin Leadless Leadframe Package (LLP-24).


    Applications

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

    • Also Recommended
    LM2796▲Dual Display White LED Driver -MicroSMD
    LP3936Inductive White Led Driver With I2C Compatible Interface



    Typical Application
    click for larger image


    		Block Diagram
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    Typical Performance
    click for larger image


    Parameters / ValuesLM27964 LM2796
    Regulated LEDs7 7
    Total LED Current180 mA 140 mA
    Current Matching0.3% 1%
    Boost TypeSwitched Capacitor Multi-Gain Switched Capacitor 1.5x
    Switching Frequency700 kHz 500 kHz
    Efficiency (peak)87 % 80 %
    Input Min Voltage2.7 Volt 2.7 Volt
    Input Max Voltage5.5 Volt 5.5 Volt
    Boost VoltageRegulated Unregulated
    LED ConfigurationParallel Parallel
    Supply Current1.3 mA 3.5 mA
    Switching TypeFixed Freq Fixed Freq
    Special FeaturesCurrent regulated output, 3 sets of outputs are common cathode using current sink topology, control by an I2C compatible interface LEDs controlled in 2 groups: 3 and 4 LEDs; softstart
    PWM BrightCtrlYes Yes
    Analog-V BrightCtrlNo No
    Ambient Light CompensationNo No
    RGB-LEDNo No
    Temperature Min-30 deg C -30 deg C
    Temperature Max85 deg C 85 deg C
    RegTypeWhiteLED Driver WhiteLED Driver
    PowerWiseNo Yes

    Datasheets
    TitleSizeDateOther
    Language
    LM27964 White LED Driver System with I2C Compatible Brightness Control330
    Kbytes    		29-Aug-07   

    Part Number(s)
    (NSID)    		Top ViewAvailabilityCurrent Reported StockBudgetary PricingPack
    Size
    LM27964SQ-C/NOPB


    RoHS Status

    LLP    		Full production
    Lead Time: 6 weeks

    Samples
    DistributorRegionQty
    DIGI-KEYWorldwide2000
    FARNELLEurope and Asia970
    MOUSERWorldwide1000
    NEWARKAmericas970
    		$1.40 each at 1K+ pcsreel
    of
    1000
    LM27964SQ-I/NOPB

    LM27964SQ-I

    RoHS Status

    LLP    		Full production
    Lead Time: 6 weeks

    Samples
    DistributorRegionQty
    DIGI-KEYWorldwide1000
    MOUSERWorldwide1000
    		$1.40 each at 1K+ pcsreel
    of
    1000
    LM27964SQX-C/NOPB


    RoHS Status

    LLP    		Full production
    Lead Time: 6 weeks

     
    DistributorRegionQty
    DIGI-KEYWorldwide0
    		$1.40 each at 1K+ pcsreel
    of
    4500
    LM27964SQX-I/NOPB

    LM27964SQX-I

    RoHS Status

    LLP    		Full production
    Lead Time: 6 weeks

     
    DistributorRegionQty
    DIGI-KEYWorldwide0
    		$1.40 each at 1K+ pcsreel
    of
    4500

    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 LM27964.

    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 LM27964 is located at RoHS Status.

    Part Number(s)
    (NSID)    		Weight
    (milligrams)    		TypePinsMSL RatingPeak ReflowRoHS
    Status    		CAD SymbolsModelsPackage
    Marking
    Format
    LM27964SQ-C/NOPB

    		39.849
    		LLP241260DetailDownloadN/A
    		NS
    UZXYTT
    27964-C
    LM27964SQ-I/NOPB

    LM27964SQ-I
    		39.849
    40.002
    		LLP241
    1    		260
    260    		DetailDownloadN/A
    		NS
    UZXYTT
    L27964S
    LM27964SQX-C/NOPB

    		39.849
    		LLP241260DetailDownloadN/A
    		NS
    UZXYTT
    27964-C
    LM27964SQX-I/NOPB

    LM27964SQX-I
    		39.849
    40.002
    		LLP241
    1    		260
    260    		DetailDownloadN/A
    		NS
    UZXYTT
    L27964S

    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 LM27964.

    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 LM27964 is located at RoHS Status.

    CAD Symbols and Models
    Download LM27964 CAD Symbols
    		 Models
    N/A


    Reliability Metrics
    Part Number Process EFR Reject EFR Sample Size PPM LTA Rejects LTA Device Hours FITS MTTF (Hours)
    LM27964SQ-CCMOS70213010015840003449464325
    LM27964SQ-ICMOS70213010015840003449464325
    LM27964SQX-CCMOS70213010015840003449464325
    LM27964SQX-ICMOS70213010015840003449464325

    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 LM27964.

    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 LM27964 is located at RoHS Status.

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