National Semiconductor | High-performance Analog

 

 LM57   
Resistor-Programmable Temperature Switch and Analog Temperature Sensor from the PowerWise® Family		 Click link to Download

Features

  • Trip temperature set by external resistors
  • External resistor tolerance contributes zero error
  • Push-pull and open-drain temperature switch outputs
  • Wide operating temperature and trip-temperature range of −50°C to 150°C
  • Very linear analog VTEMP temperature sensor output
  • Analog and digital outputs are short-circuit protected
  • TRIP-TEST pin allows in-system testing
  • Latching function for the digital outputs
  • Very small 2.5 mm by 2.5 mm 8-Pin LLP package

    • Description

    The LM57 is a precision, dual-output, temperature switch with integrated analog temperature sensor. The trip temperature (TTRIP) is programmable by using two external 1% resistors. Using extremely small packaged resistors (0.5 mm x 1 mm), the LM57 can be programmed to any of 256 trip temperatures while consuming very little board space. The VTEMP output delivers an analog output voltage which is proportional with a negative temperature coefficient (NTC) to the measured temperature.

    Built-in temperature hysteresis (THYST) keeps the output stable in an environment of thermal oscillation. The digital temperature switch outputs will go active when the die temperature exceeds TTRIP and will release when the temperature falls below a temperature equal to TTRIP minus THYST. One of the digital outputs, TOVER, is active-high with a push-pull structure. The other digital output, ^TOVER, is active-low with an open-drain structure.

    Driving the TRIP-TEST input high will make the digital outputs active. A processor can read the logic level of the temperature switch outputs, confirming that they changed to their active state. This allows for in-situ verification that the comparator and output circuitry are functional after system assembly. When the TRIP-TEST pin is high, the trip-level reference voltage appears at the Vtemp pin. The system could then use this voltage to calibrate the sensor for even tighter accuracy. Tying TOVER to TRIP-TEST will latch the output after it trips. It can be cleared by forcing TRIP-TEST low or powering off the LM57.

    As it draws only 28µA max from its supply, it has very low self-heating, about 0.02°C in still air.

    Key Specification

    Supply voltage

    2.4V to 5.5V

    Supply current

    24 μA (typ)

    Temperature switch accuracy

    ±1.5°C

    Analog (VTEMP) Accuracy

    ±0.7°C

    Operating temperature

    −50°C to 150°C

    Hysteresis magnitude

    5°C, 10°C


    Applications

  • Cell phones
  • Wireless transceivers
  • Digital cameras
  • Personal digital assistants (PDA's)
  • Battery management
  • Automotive
  • Disk drives
  • Games
  • Appliances



    • LM57 Typical Application

     

    ParametersValues
    SetPoint Type Resistor Selectable
    Temperature Accuracy (+/-) 2.3, 1.5 deg C
    Supply Min 2.4 Volt
    Temperature Min -50 deg C
    Temperature Max 150 deg C
    Quiescent Current_ 24 uA
    Comparators 1
    Sensor Gain -5.166 to -12.924 mV/C
    Supply Max 5.5 Volt
    VtempOutput Impedance 1 Ohm
    Quiescent Current 0.024 mA
    Automotive Yes
    PowerWise Yes

    Datasheets
    TitleSizeDateOther
    Language
    LM57 Resistor-Programmable Temperature Switch and Analog Temperature Sensor558
    Kbytes    		9-Feb-10   


    Application Notes
    TitleSizeDateOther
    Language
    AN-1984: Application Note 1984 LM57 Temperature Switch vs Thermistors210
    Kbytes    		28-Jul-09 

    Part Number(s)
    (NSID)    		Top ViewAvailabilityCurrent Reported StockBudgetary PricingPack
    Size
    LM57BISD-10/NOPB


    RoHS Status

    LLP    		Full production
    Lead Time: 6 weeks

    Samples
    DistributorRegionQty
    DIGI-KEYWorldwide1630
    FARNELLEurope and Asia923
    MOUSERWorldwide1000
    NEWARKAmericas923
    		$1.10 each at 1K+ pcsreel
    of
    1000
    LM57BISD-5/NOPB


    RoHS Status

    LLP    		Full production
    Lead Time: 6 weeks

    Samples
    DistributorRegionQty
    ARROWWorldwide1775
    AVNET-EMWorldwide831
    DIGI-KEYWorldwide4317
    FARNELLEurope and Asia238
    NEWARKAmericas238
    TAYLORAmericas1775
    		$1.10 each at 1K+ pcsreel
    of
    1000
    LM57BISDX-10/NOPB


    RoHS Status

    LLP    		Full production
    Lead Time: 6 weeks

     
    DistributorRegionQty
    DIGI-KEYWorldwide0
    		$1.10 each at 1K+ pcsreel
    of
    4500
    LM57BISDX-5/NOPB


    RoHS Status

    LLP    		Full production
    Lead Time: 6 weeks

     
    DistributorRegionQty
    DIGI-KEYWorldwide0
    		$1.10 each at 1K+ pcsreel
    of
    4500
    LM57CISD-10/NOPB


    RoHS Status

    LLP    		Full production
    Lead Time: 6 weeks

    Samples
    DistributorRegionQty
    AVNET-EMWorldwide899
    DIGI-KEYWorldwide1618
    FARNELLEurope and Asia895
    NEWARKAmericas895
    		$0.80 each at 1K+ pcsreel
    of
    1000
    LM57CISD-5/NOPB


    RoHS Status

    LLP    		Full production
    Lead Time: 6 weeks

    Samples
    DistributorRegionQty
    AVNET-EMWorldwide1000
    DIGI-KEYWorldwide1866
    FARNELLEurope and Asia717
    MOUSERWorldwide738
    NEWARKAmericas717
    		$0.80 each at 1K+ pcsreel
    of
    1000
    LM57CISDX-10/NOPB


    RoHS Status

    LLP    		Full production
    Lead Time: 6 weeks

     
    DistributorRegionQty
    DIGI-KEYWorldwide0
    		$0.80 each at 1K+ pcsreel
    of
    4500
    LM57CISDX-5/NOPB


    RoHS Status

    LLP    		Full production
    Lead Time: 6 weeks

     
    DistributorRegionQty
    DIGI-KEYWorldwide0
    		$0.80 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 LM57.

    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 LM57 is located at RoHS Status.

    Part Number(s)
    (NSID)    		DescriptionAvailabilityCurrent Reported StockBudgetary PricingPack
    Size
    LM57B10EB/NOPB

    		LM57 Evaluation BoardFull production
    Lead Free (RoHS)

     
    DistributorRegionQty
    DIGI-KEYWorldwide0
    FARNELLEurope and Asia3
    MOUSERWorldwide3
    NEWARKAmericas3
    		$65.00 each1

    Description:

    The LM57 is a precision, dual-output, temperature switch and temperature sensor. Switch temperature is set to one of 256 possible trip points using two external resistors. The temperature switch outputs are open drain or push pull. The temperature sensor output is inversely proportional to temperature.

    The LM57B10EB Evaluation Board simplifies connecting to the LM57BISD-10 for evaluation purposes. Other LM57 parts can be special ordered with this evaluation board.

    Contents:

    • Evaluation Board
    • LM57B10EB Kit Manual
    • Cover letter
    • LM57 Datasheet
    • Temperature Sensor Selection Guide



    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
    LM57BISD-10/NOPB

    		13.164
    		LLP83260DetailDownloadN/A
    		XYTT
    57B9
    LM57BISD-5/NOPB

    		13.164
    		LLP83260DetailDownloadN/A
    		XYTT
    57B5
    LM57BISDX-10/NOPB

    		13.164
    		LLP83260DetailDownloadN/A
    		XYTT
    57B9
    LM57BISDX-5/NOPB

    		13.164
    		LLP83260DetailDownloadN/A
    		XYTT
    57B5
    LM57CISD-10/NOPB

    		13.164
    		LLP83260DetailDownloadN/A
    		XYTT
    57C9
    LM57CISD-5/NOPB

    		13.164
    		LLP83260DetailDownloadN/A
    		XYTT
    57C5
    LM57CISDX-10/NOPB

    		13.164
    		LLP83260DetailDownloadN/A
    		XYTT
    57C9
    LM57CISDX-5/NOPB

    		13.164
    		LLP83260DetailDownloadN/A
    		XYTT
    57C5

    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 LM57.

    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 LM57 is located at RoHS Status.

    CAD Symbols and Models
    Download LM57 CAD Symbols
    		 Models
    N/A


    Reliability Metrics
    Part Number Process EFR Reject EFR Sample Size PPM LTA Rejects LTA Device Hours FITS MTTF (Hours)
    LM57BISD-10CMOS70213010015840003449464325
    LM57BISD-5CMOS70213010015840003449464325
    LM57BISDX-10CMOS70213010015840003449464325
    LM57BISDX-5CMOS70213010015840003449464325
    LM57CISD-10CMOS70213010015840003449464325
    LM57CISD-5CMOS70213010015840003449464325
    LM57CISDX-10CMOS70213010015840003449464325
    LM57CISDX-5CMOS70213010015840003449464325

    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 LM57.

    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 LM57 is located at RoHS Status.

    System Design Using the LM57 User-Programmable Temperature Switch & Sensor
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    System Design Using the LM57 User-Programmable Temperature Switch & Sensor
    Date: 2009-05-22
    Length: 0:20:00
    [Information as of 8-Feb-2012]
    Copyright © 2011 National Semiconductor Corporation