National Semiconductor | High-performance Analog

 

 LM25085A   
42V Constant On-Time PFET Buck Switching Controller with 0.9V Reference 		Click link to Download

Features

  • Wide 4.5V to 42V input voltage range
  • Adjustable current limit using RDS(ON) or a current sense resistor
  • Programmable switching frequency to 1MHz
  • No loop compensation required
  • Ultra-Fast transient response
  • Nearly constant operating frequency with line and load variations
  • Adjustable output voltage from 0.9V
  • Precision ±2% feedback reference
  • Capable of 100% duty cycle operation
  • Internal soft-start timer
  • Integrated high voltage bias regulator
  • Thermal shutdown

    • Description

    The LM25085A is a functional variant of the LM25085 COT PFET Buck Switching Controller. The functional differences of the LM25085A are: The feedback reference voltage is 0.9V, the forced off-time after current limit detection is longer, and the soft-start time is shorter (1.8 ms).

    The LM25085A is a high efficiency PFET switching regulator controller that can be used to quickly and easily develop a small, efficient buck regulator for a wide range of applications. This high voltage controller contains a PFET gate driver and a high voltage bias regulator which operates over a wide 4.5V to 42V input range. The constant on-time regulation principle requires no loop compensation, simplifies circuit implementation, and results in ultra-fast load transient response. The operating frequency remains nearly constant with line and load variations due to the inverse relationship between the input voltage and the on-time. The PFET architecture allows 100% duty cycle operation for a low dropout voltage. Either the RDS(ON) of the PFET or an external sense resistor can be used to sense current for over-current detection.

    WEBENCH® LM25085A
        Min   Max   Range  
      VIN – V    4.50 – 42.00V  
      VOUT V    0.90 – 42.00V  
      IOUT A    ≤ 10.00A  
      Ambient Temp °C    ≤ 100°C  
    Footprint BOM Cost Efficiency
    What are WEBENCH® tools?


    Also Recommended
    LM25085▲1.25V Reference Voltage
    LM5085▲Higher VIN Up To 75V



    Typical Application
    click for larger image


    		Block Diagram
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    Typical Performance
    click for larger image


    Parameters / ValuesLM25085A LM25085 LM5085
    Input Min Voltage4.5 Volt 4.5 Volt 4.5 Volt
    Input Max Voltage42 Volt 42 Volt 75 Volt
    Output Range0.9V to VIN 1.25V to VIN 1.25V to VIN
    Frequency Max1000 kHz 1000 kHz 1000 kHz
    Feedback Voltage0.9 Volt 1.25 Volt 1.25 Volt
    Feedback Tolerance2 % 2 % 2 %
    Adj Switch FrequencyYes Yes Yes
    Adjustable OutputYes Yes Yes
    Synchronous RectificationNo No No
    On/Off PinYes Yes Yes
    PowerGood / Error FlagNo No No
    SoftStartYes Yes Yes
    Sync PinNo No No
    InvertingYes Yes Yes
    FlybackNo No No
    Lossless Current SenseNo No
    RegTypeSwitching Controller Switching Controller Switching Controller
    Temperature Min-40 deg C -40 deg C -40 deg C
    Temperature Max125 deg C 125 deg C 125 deg C
    Channels1 Channels 1 Channels
    Special FeaturesNear constant switching frequency, PFET for 100% duty cycle Near constant switching frequency, PFET for 100% duty cycle Near constant switching frequency, PFET for 100% duty cycle
    TopologyBuck Buck Buck
    PWM ModeConstant On-Time (COT) Constant On-Time (COT) Constant On-Time (COT)
    Step-DownYes Yes Yes
    Step-UpNo No
    Output Min0.9 Volt 1.25 Volt
    AutomotiveNo No Yes
    PowerWiseNo Yes Yes
    Part Number(s)
    (NSID)    		Top ViewAvailabilityCurrent Reported StockBudgetary PricingPack
    Size
    LM25085AMM/NOPB


    RoHS Status

    MINI SOIC    		Full production
    Lead Time: 6 weeks

     
    DistributorRegionQty
    DIGI-KEYWorldwide0
    		$0.85 each at 1K+ pcsreel
    of
    1000
    LM25085AMME/NOPB


    RoHS Status

    MINI SOIC    		Full production
    Lead Time: 6 weeks

    Samples
    DistributorRegionQty
    ARROWWorldwide240
    AVNET-EMWorldwide500
    DIGI-KEYWorldwide422
    MOUSERWorldwide462
    TAYLORAmericas240
    		$0.85 each at 1K+ pcsreel
    of
    250
    LM25085AMMX/NOPB


    RoHS Status

    MINI SOIC    		Full production
    Lead Time: 6 weeks

     
    DistributorRegionQty
    DIGI-KEYWorldwide0
    		$0.85 each at 1K+ pcsreel
    of
    3500
    LM25085AMY/NOPB


    RoHS Status

    MINI SOIC EXP PAD    		Full production
    Lead Time: 6 weeks

     
    DistributorRegionQty
    DIGI-KEYWorldwide0
    		$0.85 each at 1K+ pcsreel
    of
    1000
    LM25085AMYE/NOPB


    RoHS Status

    MINI SOIC EXP PAD    		Full production
    Lead Time: 6 weeks

    Samples
    DistributorRegionQty
    AVNET-EMWorldwide250
    DIGI-KEYWorldwide560
    MOUSERWorldwide495
    		$0.85 each at 1K+ pcsreel
    of
    250
    LM25085AMYX/NOPB


    RoHS Status

    MINI SOIC EXP PAD    		Full production
    Lead Time: 8 weeks

     
    DistributorRegionQty
    DIGI-KEYWorldwide0
    		$0.85 each at 1K+ pcsreel
    of
    3500
    LM25085ASD/NOPB


    RoHS Status

    LLP    		Full production
    Lead Time: 6 weeks

     
    DistributorRegionQty
    DIGI-KEYWorldwide0
    		$0.85 each at 1K+ pcsreel
    of
    1000
    LM25085ASDE/NOPB


    RoHS Status

    LLP    		Full production
    Lead Time: 6 weeks

    Samples
    DistributorRegionQty
    DIGI-KEYWorldwide745
    MOUSERWorldwide500
    		$0.85 each at 1K+ pcsreel
    of
    250
    LM25085ASDX/NOPB


    RoHS Status

    LLP    		Full production
    Lead Time: 6 weeks

     
    DistributorRegionQty
    DIGI-KEYWorldwide0
    		$0.85 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 LM25085A.

    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 LM25085A is located at RoHS Status.

    Part Number(s)
    (NSID)    		DescriptionAvailabilityCurrent Reported StockBudgetary PricingPack
    Size
    LM25085AMYEEVAL
    		LM25085AMYEEVAL 42V Constant On-Time PFET Buck Switching Controller with 0.9V ReferenceFull production


     
    DistributorRegionQty
    		$75.00 each1

    Description:

    The LM25085AMYE evaluation board provides the design engineer with a fully functional buck regulator, employing the LM25085A PFET switching controller which uses the constant on-time (COT) operating principle. This evaluation board provides a 1V output over an input range of 4.5V to 24V. The circuit delivers load currents to 5A, with current limit set at ≅8.2A. The board is populated with all components except C5 and C7.

    Contents:




    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
    LM25085AMM/NOPB

    		29.851
    		MINI SOIC81260DetailDownloadN/A
    		ZXTT
    SVZA
    LM25085AMME/NOPB

    		29.851
    		MINI SOIC81260DetailDownloadN/A
    		ZXTT
    SVZA
    LM25085AMMX/NOPB

    		29.851
    		MINI SOIC81260DetailDownloadN/A
    		ZXTT
    SVZA
    LM25085AMY/NOPB

    		29.851
    		MINI SOIC EXP PAD81260DetailDownloadN/A
    		ZXTT
    SVYA
    LM25085AMYE/NOPB

    		29.851
    		MINI SOIC EXP PAD81260DetailDownloadN/A
    		ZXTT
    SVYA
    LM25085AMYX/NOPB

    		29.851
    		MINI SOIC EXP PAD81260DetailDownloadN/A
    		ZXTT
    SVYA
    LM25085ASD/NOPB

    		20.736
    		LLP81260DetailDownloadN/A
    		ZXYTT
    L246A
    LM25085ASDE/NOPB

    		20.736
    		LLP81260DetailDownloadN/A
    		ZXYTT
    L246A
    LM25085ASDX/NOPB

    		20.736
    		LLP81260DetailDownloadN/A
    		ZXYTT
    L246A

    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 LM25085A.

    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 LM25085A is located at RoHS Status.

    Design Tools
    TitleSizeDate
    LM25085A Quick Start Calculator  

    CAD Symbols and Models
    Download LM25085A CAD Symbols
    		 Models
    N/A


    Reliability Metrics
    Part Number Process EFR Reject EFR Sample Size PPM LTA Rejects LTA Device Hours FITS MTTF (Hours)
    LM25085AMMABCD150XV1038680025950002736338335
    LM25085AMMEABCD150XV1038680025950002736338335
    LM25085AMMXABCD150XV1038680025950002736338335
    LM25085AMYABCD150XV1038680025950002736338335
    LM25085AMYEABCD150XV1038680025950002736338335
    LM25085AMYXABCD150XV1038680025950002736338335
    LM25085ASDABCD150XV1038680025950002736338335
    LM25085ASDEABCD150XV1038680025950002736338335
    LM25085ASDXABCD150XV1038680025950002736338335

    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 LM25085A.

    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 LM25085A is located at RoHS Status.

    LM25085/5085 Implementing Accurate Current Limit Demo
    Loading video...


    LM25085/5085 Implementing Accurate Current Limit Demo
    Date: 2011-07-29
    Length: 00:03:24
    [Information as of 9-Feb-2012]
    Copyright © 2011 National Semiconductor Corporation