National Semiconductor | High-performance Analog

 

 LM2743   
Low Voltage N-Channel MOSFET Synchronous Buck Regulator Controller from the PowerWise® Family		 Click link to Download

Features

  • Power stage input voltage from 1V to 16V
  • Control stage input voltage from 3V to 6V
  • Output voltage adjustable down to 0.6V
  • Power good flag and shutdown
  • Output over-voltage and under-voltage detection
  • ±2% feedback voltage accuracy over temperature
  • Low-side adjustable current sensing
  • Adjustable soft-start
  • Tracking and sequencing with shutdown and soft-start pins
  • Switching frequency from 50 kHz to 1 MHz
  • TSSOP-14 package

    • Description

    The LM2743 is a high-speed synchronous buck regulator controller with an accurate feedback voltage accuracy of ±2%. It can provide simple down conversion to output voltages as low as 0.6V. Though the control sections of the IC are rated for 3 to 6V, the driver sections are designed to accept input supply rails as high as 16V. The use of adaptive non-overlapping MOSFET gate drivers helps avoid potential shoot-through problems while maintaining high efficiency. The IC is designed for the more cost-effective option of driving only N-channel MOSFETs in both the high-side and low-side positions. It senses the low-side switch voltage drop for providing a simple, adjustable current limit.

    The fixed-frequency voltage-mode PWM control architecture is adjustable from 50 kHz to 1 MHz with one external resistor. This wide range of switching frequency gives the power supply designer the flexibility to make better tradeoffs between component size, cost and efficiency.

    Features include soft-start, input under-voltage lockout (UVLO) and Power Good (based on both under-voltage and over-voltage detection). In addition, the shutdown pin of the IC can be used for providing startup delay, and the soft-start pin can be used for implementing precise tracking, for the purpose of sequencing with respect to an external rail.


    Applications

  • 3.3V Buck Regulation
  • Cable Modem, DSL and ADSL
  • Laser Jet and Ink Jet Printers
  • Low Voltage Power Modules
  • DSP, ASIC, Core and I/O

    • WEBENCH® LM2743
        Min   Max   Range  
      VIN – V    1.00 – 16.00V  
      VOUT V    0.60 – 12.00V  
      IOUT A    ≤ 20.00A  
      Ambient Temp °C    ≤ 100°C  
    Footprint BOM Cost Efficiency
    What are WEBENCH® tools?


    Also Recommended
    LM2647Dual Channel, 28V Max Vin
    LM2745▲Frequency Synchronization And Starts Up With Pre-biased Loads
    LM2747▲Frequency Synchronization, Starts Up With Pre-biased Loads, +/-1% Accuracy
    LM2748▲Starts Up With Pre-Biased Loads, +/-1.5% Accuracy
    LM3743▲Low-Voltage Sync Buck Controller In MSOP-10
    LM2746▲+/-1% Accuracy



    Typical Application
    click for larger image


    		Block Diagram
    click for larger image



    Typical Performance
    click for larger image


    Parameters / ValuesLM2743 LM2745 LM2747 LM2748 LM3743 LM2746
    Output Current20000 mA 20000 mA 20000 mA 20000 mA 10000 mA
    Input Min Voltage1 Volt 1 Volt 1 Volt 1 Volt 3 Volt
    Input Max Voltage16 Volt 17 Volt 17 Volt 16 Volt 5.5 Volt
    Feedback Voltage0.6 Volt 0.6 Volt 0.6 Volt 0.6 Volt 0.8 Volt
    Frequency Min50 kHz 50 kHz 50 kHz 50 kHz 300 kHz
    Frequency Max2000 kHz 1000 kHz 1000 kHz 1000 kHz 1000 kHz
    Efficiency (peak)85 % 85 % 85 % 85 % 95 %
    Output Range0.6V to 13.5V 0.6V to 13.5V 0.6V to 13.5V 0.6V to 13.5V 0.8V to 4.6V
    Adj Switch FrequencyYes Yes Yes Yes No
    Adjustable OutputYes Yes Yes Yes Yes
    On/Off PinYes Yes Yes Yes Yes
    PowerGood / Error FlagYes Yes Yes Yes No
    SoftStartYes Yes Yes Yes Yes
    Sync PinNo Yes Yes No No
    InvertingNo No No No No
    FlybackNo No No No No
    Lossless Current SenseYes Yes Yes Yes Yes
    RegTypeSwitching Controller Switching Controller Switching Controller Switching Controller Switching Regulator
    Temperature Min-40 deg C -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 125 deg C
    Channels1 Channels 1 Channels 1 Channels 1 Channels 1 Channels
    Special Features2.7V UVLO; Tri-State output during SD; Tracking; Precision SD threshold Pre-bias startup; 40ns min on-time Pre-bias startup; 40ns min on-time Pre-bias startup; 40ns min on-time Pre-bias start-up; Hiccup mode; External programmable soft-start and tracking
    TopologyBuck Buck Buck Buck Buck
    PWM ModeVoltage Voltage Voltage Voltage Voltage
    Step-DownYes Yes Yes Yes Yes
    Step-UpNo No No No No
    Output PowerUndefined Watt Undefined Watt Undefined Watt Undefined Watt Undefined Watt
    Output Max13.5 Volt 13.5 Volt 13.5 Volt 13.5 Volt 4.6 Volt
    Output Min0.6 Volt 0.6 Volt 0.6 Volt 0.6 Volt 0.8 Volt
    PowerWiseYes Yes Yes Yes Yes
    Part Number(s)
    (NSID)    		Top ViewAvailabilityCurrent Reported StockBudgetary PricingPack
    Size
    LM2743MTC/NOPB

    LM2743MTC

    RoHS Status

    TSSOP    		Full production
    Lead Time: 6 weeks

    Samples
    DistributorRegionQty
    ARROWWorldwide13089
    AVNET-EMWorldwide85
    DIGI-KEYWorldwide2014
    FARNELLEurope and Asia287
    MOUSERWorldwide272
    TAYLORAmericas13089
    TECHMOSAAsia Pacific1
    		$1.15 each at 1K+ pcsrail
    of
    94
    LM2743MTCX/NOPB

    LM2743MTCX

    RoHS Status

    TSSOP    		Full production
    Lead Time: 6 weeks

     
    DistributorRegionQty
    AVNET-EMWorldwide2500
    DIGI-KEYWorldwide0
    MOUSERWorldwide2450
    TECHMOSAAsia Pacific9906
    		$1.15 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 LM2743.

    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 LM2743 is located at RoHS Status.

    Part Number(s)
    (NSID)    		DescriptionAvailabilityCurrent Reported StockBudgetary PricingPack
    Size
    LM2743-19AEVAL
    		Low Voltage N-Channel MOSFET Synchronous Buck Regulator ControllerFull production


     
    DistributorRegionQty
    DIGI-KEYWorldwide0
    MOUSERWorldwide1
    		$79.70 each1

    Features:

    • Power stage input voltage from 1V to 16V
    • Control stage input voltage from 3V to 6V
    • Output voltage adjustable down to 0.6V
    • Power good flag and shutdown
    • Output overvoltage and undervoltage detection
    • ± 2% feedback voltage accuracy over temperature
    • Low-side adjustable current sensing
    • Adjustable soft-start
    • Tracking and sequencing with shutdown and soft start pins
    • Switching frequency from 50 kHz to 1 MHz
    • TSSOP-14 package

    Applications:

    • 3.3V Buck Regulation
    • Cable Modem, DSL and ADSL
    • Laser Jet and Ink Jet Printers
    • Low Voltage Power Modules
    • DSP, ASIC, Core and I/O

    Contents:

    • A LM2743-19A Fully Assembled Evaluation Board
    • A LM2743 Datasheet
    • A LM2743 Evaluation Board Appnote

    Part Number(s)
    (NSID)    		DescriptionAvailabilityCurrent Reported StockBudgetary PricingPack
    Size
    LM2743EVAL/NOPB

    		Low Voltage N-Channel MOSFET Synchronous Buck Regulator ControllerFull production
    Lead Free (RoHS)

     
    DistributorRegionQty
    DIGI-KEYWorldwide0
    MOUSERWorldwide1
    		$79.70 each1

    Description:

    LM2743 N-Channel FET Synchronous Buck Regulator Controller for Conversion from 3.3V

    Features:

    • MOSFET input voltage (VIN) from 1V to 16V
    • IC Input voltage (VCC) from 3V to 6V
    • Output voltage adjustable down to 0.6V
    • Power good flag and output enable
    • Output over-voltage and under-voltage flag
    • FB voltage: 2% over temperature
    • Current limit without series sense resistor
    • Adjustable soft start
    • Tracking and sequencing with shutdown and soft start pins
    • Switching frequency from 50 kHz to 2 MHz
    • TSSOP-14 package

    Applications:

    • 3.3V Buck Regulation
    • Set-top Boxes/Home Gateways
    • Core Logic Regulators
    • High-Efficiency Buck Regulation

    Contents:

    • A fully assembled LM2743 evaluation board
    • LM2743 datasheet (includes LM2743 eval board appnote)



    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
    LM2743MTC/NOPB

    LM2743MTC
    		53.783
    54.004
    		TSSOP141
    1    		260
    260    		DetailDownloadN/A
    		NSZXYTT
    2743
    MTC
    LM2743MTCX/NOPB

    LM2743MTCX
    		53.783
    54.004
    		TSSOP141
    1    		260
    260    		DetailDownloadN/A
    		NSZXYTT
    2743
    MTC

    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 LM2743.

    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 LM2743 is located at RoHS Status.

    Reliability Metrics
    Part Number Process EFR Reject EFR Sample Size PPM LTA Rejects LTA Device Hours FITS MTTF (Hours)
    LM2743MTCABCD15004268000639400011814314958
    LM2743MTCXABCD15004268000639400011814314958

    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 LM2743.

    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 LM2743 is located at RoHS Status.

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