National Semiconductor | High-performance Analog

 

 LM49250   

Enhanced Emissions Suppression Stereo Class D Audio Sub-System with Ground Referenced Headphone Amplifier from the PowerWise® Family
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Features

  • Output Short Circuit Protection
  • Thermal Overload Protection
  • Stereo filterless Class D operation
  • Spread spectrum modulation
  • Ground referenced Headphone Drivers
  • I 2C Control Interface
  • 32-step input volume control
  • Output volume control
  • Minimum external components
  • Click and Pop suppression
  • Micro-power shutdown
  • Available in space-saving 36–bump µSMD package
  • Single supply operation
  • RF suppression
  • Description

    The LM49250 is a fully integrated audio subsystem designed for stereo cell phone applications. The LM49250 combines a 2.4W/Ch stereo class D speaker amplifiers with a 45mW/Ch stereo ground referenced headphone amplifier, a class AB earpiece amplifier, National 3D enhancement, volume control, and an input mixer into a single device. The filterless class D amplifiers deliver 1.2W/Ch into an 8Ω load with <1% THD+N from a 5V supply.

    The LM49250 features a new circuit technology that utilizes a charge pump to generate a negative supply voltage. This allows the headphone outputs to be biased about ground, thereby eliminating the output-coupling capacitors.

    For improved noise immunity, the LM49250 features fully differential left, right and mono inputs. The three inputs can be mixed/multiplexed to any output combination of the loudspeaker, headphone or earpiece amplifiers. The left and right differential inputs can be used as separate single-ended inputs, mixing multiple stereo audio sources. The mixer, volume control, and device mode select are controlled through an I 2C compatible interface.

    Output short circuit and thermal overload protection prevent the device from being damaged during fault conditions. Superior click and pop suppression eliminates audible transients on power-up/down and during shutdown.

    Key Specification
    Power Output at VDD = 5V  
     Speaker:   RL = 4Ω, THD+N 1%   RL = 4Ω, THD+N 10%   RL = 8Ω, THD+N 1% 1.97W/Ch 2.4W/Ch 1.2W/Ch
     Headphone:   RL = 16Ω, THD+N 1%   RL = 32Ω, THD+N 1% 41mW/Ch 45mW/Ch
     Earpiece:   RL = 16Ω, THD+N 1%   RL = 32Ω, THD+N 1% 170mW 90mW
    Shutdown Current 0.1μA
    Efficiency at 5V, 1W into 8Ω 87%
    Efficiency at 3.6V, 500mW into 8Ω 85%


    Applications

  • Mobile phones
  • Portable Navigation Devices
  • Portable Media Players



  • Typical Application
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    Connection Diagram
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    Typical Performance
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    ParametersValues
    Power @ 5V 8Ohms, 1% THD 1.23 Watt
    Speaker THD+N 0.02 %
    HP THD+N 0.015 %
    Speaker PSRR 95 dB
    HP PSRR 95 dB
    Speaker SNR Undefined dB
    Audio Mux Yes
    Audio Mode Control I2C
    Supply Range +2.7 - +5.5 V
    Temperature Min -40 deg C
    Temperature Max 85 deg C
    Mono Analog Inputs 1
    Stereo Analog Inputs 2
    Digital Audio Ports 0
    Additional Audio Features National 3D
    Loudspeaker Type Class D
    Loudspeaker Outputs 2
    Headphone Type True Ground
    AEC Q-100 Automotive Grade Undefined
    PowerWise Yes

    Datasheets
    TitleSizeDateOther
    Language
    LM49250 Enhanced Emissions Suppression Stereo Class D Audio Sub-System with Ground Referenced Headphone Amplifier1350
    Kbytes
    15-Dec-08   


    Application Notes
    TitleSizeDateOther
    Language
    AN-1680: Application Note 1680 LM49250 Evaluation Board User Guide1231
    Kbytes
    9-Mar-10 

    Part Number(s)
    (NSID)
    Top ViewAvailabilityCurrent Reported StockBudgetary PricingPack
    Size
    LM49250RL/NOPB


    RoHS Status


    MICRO SMDXT
    Full production
    Lead Time: 6 weeks

    Samples
    DistributorRegionQty
    DIGI-KEYWorldwide434
    MOUSERWorldwide250
    $2.40 each at 1K+ pcsreel
    of
    250
    LM49250RLX/NOPB


    RoHS Status


    MICRO SMDXT
    Full production
    Lead Time: 6 weeks

     
    DistributorRegionQty
    DIGI-KEYWorldwide0
    $2.40 each at 1K+ pcsreel
    of
    1000

    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 LM49250.

    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 LM49250 is located at RoHS Status.

    Part Number(s)
    (NSID)
    Weight
    (milligrams)
    TypePinsMSL RatingPeak ReflowRoHS
    Status
    CAD SymbolsModelsPackage
    Marking
    Format
    LM49250RL/NOPB

    10.899
    MICRO SMDXT361260DetailDownloadN/A
    XYTT
    I GJ1
    LM49250RLX/NOPB

    10.899
    MICRO SMDXT361260DetailDownloadN/A
    XYTT
    I GJ1

    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 LM49250.

    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 LM49250 is located at RoHS Status.

    CAD Symbols and Models
    Download LM49250 CAD Symbols
     Models
    N/A


    [Information as of 9-Feb-2012]