National Semiconductor | High-performance Analog

 

 LM20333   

36V, 3A Synchronous Buck Regulator with Frequency Synchronization 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
  • 94% peak efficiency with synchronous rectification
  • 1.5% feedback voltage accuracy
  • Current mode control, selectable compensation
  • Oscillator synchronization from 250kHz to 1.5MHz
  • Adjustable output voltage down to 0.8V
  • Compatible with pre-biased loads
  • Programmable soft-start with external capacitor
  • Precision enable pin with hysteresis
  • OVP, UVLO inputs and PGOOD output
  • 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 LM20333 is a full featured 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 LM20333 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 LM20333 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 switching frequency of the LM20333 can be synchronized to an external clock by use of the SYNC pin. The SYNC pin is capable of synchronizing to input signals ranging from 250 kHz to 1.5 MHz.

    The LM20333 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® LM20333
        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
    LM2034336Vin, Resistor-programmed Switching Frequency
    LM213055A Output Current, LLP-28 Package
    LM310242Vin, No Loop Compensation Required



    Typical Application
    *click for larger image


    Block Diagram
    click for larger image



    Typical Performance
    click for larger image


    Parameters / ValuesLM20333 LM20343 LM21305 LM3102
    Output Current3000 mA 3000 mA 5000 mA 2500 mA
    Input Min Voltage4.5 Volt 4.5 Volt 3 Volt 4.5 Volt
    Input Max Voltage36 Volt 36 Volt 18 Volt 42 Volt
    Output Min0.8 Volt 0.8 Volt 0.6 Volt 0.8 Volt
    Output Max32 Volt 32 Volt 5 Volt 7 Volt
    Frequency Min250 kHz 250 kHz 300 kHz Undefined kHz
    Frequency Max1500 kHz 1000 kHz 1500 kHz 1000 kHz
    Efficiency (peak)94 % 94 % 95 % 92 %
    Integrated InductorNo No No No
    PowerGood / Error FlagYes Yes Yes No
    SoftStartYes Yes Yes Yes
    Sync PinYes Yes Yes No
    InvertingNo No No No
    FlybackNo No No 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 85 deg C 125 deg C
    Adjustable OutputYes Yes Yes Yes
    Adj Switch FrequencyYes Yes Yes Yes
    PWM ModeCurrent Mode Control Current Mode Control Current Mode Control Constant On-time
    TopologySynchronous Buck Synchronous Buck Synchronous Buck Synchronous Buck
    Special FeaturesUndefined Undefined FCIC
    Step-DownYes Yes Yes Yes
    Multiple Output CapabilityNo No No No
    Output PowerUndefined Watt Undefined Watt Undefined Watt
    Output VoltageUndefined Volt Undefined Volt Undefined Volt
    Output RangeUndefined Undefined 0.6V to 5V .8-7V
    Switching FrequencyUndefined kHz Undefined kHz 300 kHz 1000 kHz
    Feedback VoltageUndefined Volt 0.8 Volt 0.6 Volt
    On/Off PinYes Yes Yes Yes
    Regulator FamilyLM20k LM20k LM20k SIMPLE SWITCHER
    AEC Q-100 Automotive GradeUndefined Undefined
    AutomotiveYes Yes No Yes
    PowerWiseYes Yes Yes Yes
    Synchronous RectificationYes Yes Yes Yes
    Quiescent Current2.3 mA 9 mA

    Datasheets
    TitleSizeDateOther
    Language
    LM20333 36V, 3A Synchronous Buck Regulator with Frequency Synchronization525
    Kbytes
    20-Jan-09日本語  


    Application Notes
    TitleSizeDateOther
    Language
    AN-1791: Application Note 1791 LM20333 Evaluation Board865
    Kbytes
    1-Oct-08 

    Part Number(s)
    (NSID)
    Top ViewAvailabilityCurrent Reported StockBudgetary PricingPack
    Size
    LM20333MH/NOPB


    RoHS Status


    TSSOP EXP PAD
    Full production
    Lead Time: 6 weeks

    Samples
    DistributorRegionQty
    ARROWWorldwide829
    DIGI-KEYWorldwide778
    FARNELLEurope and Asia186
    MOUSERWorldwide137
    TAYLORAmericas829
    $1.50 each at 1K+ pcsrail
    of
    73
    LM20333MHE/NOPB


    RoHS Status


    TSSOP EXP PAD
    Full production
    Lead Time: 8 weeks

     
    DistributorRegionQty
    AVNET-EMWorldwide250
    DIGI-KEYWorldwide0
    MOUSERWorldwide214
    $1.50 each at 1K+ pcsreel
    of
    250
    LM20333MHX/NOPB


    RoHS Status


    TSSOP EXP PAD
    Full production
    Lead Time: 8 weeks

     
    DistributorRegionQty
    DIGI-KEYWorldwide0
    $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 LM20333.

    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 LM20333 is located at RoHS Status.

    Part Number(s)
    (NSID)
    DescriptionAvailabilityCurrent Reported StockBudgetary PricingPack
    Size
    LM20333EVAL
    Evaluation Board for the LM20333Full production


     
    DistributorRegionQty
    DIGI-KEYWorldwide0
    MOUSERWorldwide2
    $55.00 each1

    Description:

    This evaluation board provides a solution to examine the full featured LM20333 buck switching regulator that is capable of driving up to 3A of load current. This device features a clock synchronization input that allows the switching frequency to be synchronized to an external clock source. The flexibility to synchronize the switching frequency from 250 kHz to 1.5 MHz allows the size of the power stage components to be reduced while still allowing for high efficiency. This board is capable of down converting from an input voltage between 4.5V and 36V. The LM20333 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 LM20333 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
    • Datasheet
    • Application Note - 1791



    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
    LM20333MH/NOPB

    73.06
    TSSOP EXP PAD201260DetailDownloadN/A
    NSUZXYTT
    20333MH
    LM20333MHE/NOPB

    73.06
    TSSOP EXP PAD201260DetailDownloadN/A
    NSUZXYTT
    20333MH
    LM20333MHX/NOPB

    73.06
    TSSOP EXP PAD201260DetailDownloadN/A
    NSUZXYTT
    20333MH

    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 LM20333.

    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 LM20333 is located at RoHS Status.

    Design Tools
    TitleSizeDate
    Download LM20333 Calculator spreadsheet  

    CAD Symbols and Models
    Download LM20333 CAD Symbols
     Models
    N/A


    Reliability Metrics
    Part Number Process EFR Reject EFR Sample Size PPM LTA Rejects LTA Device Hours FITS MTTF (Hours)
    LM20333MHABCD15004268000639400011814314958
    LM20333MHEABCD15004268000639400011814314958
    LM20333MHXABCD15004268000639400011814314958

    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 LM20333.

    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 LM20333 is located at RoHS Status.

    LM21212/15 15A Adjustable Current Buck Regulator Overview
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    LM21212/15 15A Adjustable Current Buck Regulator Overview
    Date: 2011-02-16
    Length: 00:04:50
    [Information as of 9-Feb-2012]