National Semiconductor | High-performance Analog

 

 LM20323   

36V,3A 500 kHz Synchronous Buck Regulator from the PowerWise® Family
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Features

  • 4.5V to 36V input voltage range
  • 3A output current, 5.2A peak current
  • 130 mΩ/110 mΩ integrated power MOSFETs
  • 93% peak efficiency with synchronous rectification
  • 1.5% feedback voltage accuracy
  • Current mode control, selectable compensation
  • Fixed 500 kHz switching frequency
  • Adjustable output voltage down to 0.8V
  • Compatible with pre-biased loads
  • Programmable soft-start with external capacitor
  • Precision enable pin with hysteresis
  • Integrated OVP, UVLO, PGOOD
  • Internally protected with peak current limit, thermal shutdown and restart
  • Accurate current limit minimizes inductor size
  • Non-linear current mode slope compensation
  • eTSSOP-20 exposed pad package
  • Description

    The LM20323 is a full featured 500kHz synchronous buck regulator capable of delivering up to 3A of load current. The current mode control loop is externally compensated with only two components, offering both high performance and ease of use. The device is optimized to work over the input voltage range of 4.5V to 36V making it well suited for high voltage systems.

    The device features internal Over Voltage Protection (OVP) and Over Current Protection (OCP) circuits for increased system reliability. A precision Enable pin and integrated UVLO allows the turn-on of the device to be tightly controlled and sequenced. Startup inrush currents are limited by both an internally fixed and externally adjustable soft-start circuit. Fault detection and supply sequencing are possible with the integrated power good (PGOOD) circuit.

    The LM20323 is designed to work well in multi-rail power supply architectures. The output voltage of the device can be configured to track a higher voltage rail using the SS/TRK pin. If the output of the LM20323 is pre-biased at startup it will not sink current to pull the output low until the internal soft-start ramp exceeds the voltage at the feedback pin.

    The LM20323 is offered in an exposed pad 20-pin eTSSOP package that can be soldered to the PCB, eliminating the need for bulky heatsinks.


    Applications

  • Simple to design, high efficiency point of load regulation from a 4.5V to 36V bus
  • High Performance DSPs, FPGAs, ASICs and Microprocessors
  • Communications Infrastructure, Automotive
  • WEBENCH® LM20323
        Min   Max   Range  
      VIN V    4.50 – 36.00V  
      VOUT V    0.80 – 32.00V  
      IOUT A    ≤ 3.00A  
      Ambient Temp °C    ≤ 100°C  
    Footprint BOM Cost Efficiency
    What are WEBENCH® tools?


    Also Recommended
    LM3100Simple Switcher Synchronous 1MHz 1.5A Step-Down Voltage Regulator
    LM3102Simple Switcher Synchronous 1MHz 2.5A Step-Down Voltage Regulator
    LM3103Simple Switcher Synchronous 1MHz 750mA Step-Down Voltage Regulator



    Typical Application
    *click for larger image


    Block Diagram
    click for larger image



    Typical Performance
    click for larger image


    Parameters / ValuesLM20323 LM3100 LM3102 LM3103
    Output Current3000 mA 1500 mA 2500 mA 750 mA
    Input Min Voltage4.5 Volt 4.5 Volt 4.5 Volt 4.5 Volt
    Input Max Voltage36 Volt 36 Volt 42 Volt 42 Volt
    Output Min0.8 Volt 0.8 Volt 0.8 Volt 0.6 Volt
    Output Max32 Volt 7 Volt 7 Volt 7 Volt
    Frequency MinUndefined kHz Undefined kHz Undefined kHz Undefined kHz
    Frequency MaxUndefined kHz 1000 kHz 1000 kHz 1000 kHz
    Efficiency (peak)94 % 86 % 92 % 91 %
    Integrated InductorNo No No No
    PowerGood / Error FlagYes No No No
    SoftStartYes Yes Yes Yes
    Sync PinNo No No No
    InvertingNo No No No
    FlybackNo No Yes Yes
    RegTypeSwitching Regulator Switching Regulator Switching Regulator Switching Regulator
    Temperature Min-40 deg C -40 deg C -40 deg C -40 deg C
    Temperature Max125 deg C 125 deg C 125 deg C 125 deg C
    Adjustable OutputYes Yes Yes Yes
    Adj Switch FrequencyNo Yes Yes Yes
    PWM ModeCurrent Mode Control Constant On-time Constant On-time Constant On-time
    TopologySynchronous Buck Synchronous Buck Synchronous Buck Synchronous Buck
    Special FeaturesUndefined Vin feed forward and Current Injection compensation, SIMPLE SWITCHER synchronous regulator FCIC FCIC
    Step-DownYes Yes Yes Yes
    Multiple Output CapabilityNo No No No
    Output PowerUndefined Watt Undefined Watt Undefined Watt Undefined Watt
    Output VoltageUndefined Volt Undefined Volt Undefined Volt Undefined Volt
    Output RangeUndefined 0.8V to 7V .8-7V .6-7V
    Switching Frequency500 kHz 1000 kHz 1000 kHz 1000 kHz
    Feedback Voltage0.8 Volt Undefined Volt
    On/Off PinYes Yes Yes Yes
    Regulator FamilyLM20k SIMPLE SWITCHER SIMPLE SWITCHER SIMPLE SWITCHER
    AEC Q-100 Automotive GradeUndefined
    AutomotiveYes Yes Yes Yes
    PowerWiseYes Yes Yes Yes
    Synchronous RectificationYes Yes Yes Yes

    Datasheets
    TitleSizeDateOther
    Language
    LM20323 36V,3A 500 kHz Synchronous Buck Regulator491
    Kbytes
    14-Jan-09日本語  


    Application Notes
    TitleSizeDateOther
    Language
    AN-1790: Application Note 1790 LM20323 Evaluation Board940
    Kbytes
    1-Oct-08 
    AN-1792: Application Note 1792 LM20343 Evaluation Board922
    Kbytes
    1-Oct-08 

    Part Number(s)
    (NSID)
    Top ViewAvailabilityCurrent Reported StockBudgetary PricingPack
    Size
    LM20323MH/NOPB


    RoHS Status


    TSSOP EXP PAD
    Full production
    Lead Time: 6 weeks

    Samples
    DistributorRegionQty
    AVNET-EMWorldwide64
    DIGI-KEYWorldwide5
    FARNELLEurope and Asia182
    MOUSERWorldwide214
    $1.50 each at 1K+ pcsrail
    of
    73
    LM20323MHE/NOPB


    RoHS Status


    TSSOP EXP PAD
    Full production
    Lead Time: 6 weeks

     
    DistributorRegionQty
    DIGI-KEYWorldwide0
    $1.50 each at 1K+ pcsreel
    of
    250
    LM20323MHX/NOPB


    RoHS Status


    TSSOP EXP PAD
    Full production
    Lead Time: 6 weeks

     
    DistributorRegionQty
    DIGI-KEYWorldwide0
    MOUSERWorldwide2500
    $1.50 each at 1K+ pcsreel
    of
    2500

    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 LM20323.

    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 LM20323 is located at RoHS Status.

    Part Number(s)
    (NSID)
    DescriptionAvailabilityCurrent Reported StockBudgetary PricingPack
    Size
    LM20323EVAL
    Evaluation Board for the LM20323Full production


     
    DistributorRegionQty
    DIGI-KEYWorldwide0
    MOUSERWorldwide1
    $55.00 each1

    General Description:

    This evaluation board provides a solution to examine the full featured LM20323 buck switching regulator that is capable of driving up to 3A of load current. The device features a 500 kHz fixed oscillator allowing the device to reach a good compromise between switching losses and inductor size. This board is capable of down converting from an input voltage between 4.5V and 36V. The LM20323 evaluation board has been optimized to work from 4.5V to 25V achieving a balance between overall solution size and the efficiency of the regulator. The power stage and compensation components of the LM20323 evaluation board have been optimized for an input voltage of 12V, but for testing purposes, the input can be varied across the entire operating range. The output voltage of the evaluation board is nominally 3.3V, but this voltage can be easily changed by replacing one of the feedback resistors (R5 or R6).

    Contents:

    • Assembled Evaluation Board
    • LM20323 Datasheet
    • Application Note - 1790



    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
    LM20323MH/NOPB

    73.06
    73.591
    TSSOP EXP PAD201260DetailDownloadN/A
    NSUZXYTT
    20323MH
    LM20323MHE/NOPB

    73.06
    TSSOP EXP PAD201260DetailDownloadN/A
    NSUZXYTT
    20323MH
    LM20323MHX/NOPB

    73.06
    TSSOP EXP PAD201260DetailDownloadN/A
    NSUZXYTT
    20323MH

    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 LM20323.

    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 LM20323 is located at RoHS Status.

    Design Tools
    TitleSizeDate
    Download LM20323 Calculator spreadsheet  

    CAD Symbols and Models
    Download LM20323 CAD Symbols
     Models
    N/A


    Reliability Metrics
    Part Number Process EFR Reject EFR Sample Size PPM LTA Rejects LTA Device Hours FITS MTTF (Hours)
    LM20323MHABCD15004268000639400011814314958
    LM20323MHEABCD15004268000639400011814314958
    LM20323MHXABCD15004268000639400011814314958

    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 LM20323.

    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 LM20323 is located at RoHS Status.

    [Information as of 9-Feb-2012]