SNIS191A July   2015  – July 2015 LM57-Q1

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Device Comparison Table
  5. 5 Pin Configuration and Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Switching Characteristics
    7. 6.7 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 LM57-Q1 VTEMP Temperature-to-Voltage Transfer Function
        1. 7.3.1.1 LM57-Q1 VTEMP Voltage-to-Temperature Equations
      2. 7.3.2 RSENSE
      3. 7.3.3 Resistor Selection
      4. 7.3.4 TOVER and TOVER Digital Outputs
        1. 7.3.4.1 TOVER and TOVER Noise Immunity
      5. 7.3.5 Trip Test Digital Input
      6. 7.3.6 VTEMP Analog Temperature Sensor Output
        1. 7.3.6.1 VTEMP Noise Considerations
        2. 7.3.6.2 VTEMP Capacitive Loads
        3. 7.3.6.3 VTEMP Voltage Shift
    4. 7.4 Device Functional Modes
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 ADC Input Considerations
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Selection of RSENSE Resistors
      3. 8.2.3 Application Curves
      4. 8.2.4 Grounding of the TRIP TEST Pin
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
    3. 10.3 Temperature Considerations
  11. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 Community Resources
    3. 11.3 Trademarks
    4. 11.4 Electrostatic Discharge Caution
    5. 11.5 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

1 Features

  • Qualified for Automotive Applications, for Commercial Device See LM57 Data Sheet
  • AEC-Q100 Qualified with the Following Results:
    • Temperature Grade 0 Extended: −50°C to +160°C with Excursions up to 170°C Operating Temperature Range
    • Temperature Grade 0: −50°C to +150°C Operating Temperature Range
    • Temperature Grade 1: −50°C to +125°C Operating Temperature Range
    • HBM ESD Component Classification Level 2
    • CDM ESD Component Classification Level C5
  • Trip Temperature Set by External Resistors with
    Accuracy of ±2.3°C from −40°C to +150°C
  • Resistor Tolerance Contributes Zero Error
  • Push-Pull and Open-Drain Switch Outputs
  • Wide Operating Temperature Range of −50°C to 160°C
  • Very Linear Analog VTEMP Temp Sensor Output
    with ±1.3°C Accuracy from −50°C to +150°C
  • Short-Circuit Protected Analog and Digital Outputs
  • Latching Function for Digital Outputs
  • TRIP-TEST Pin Allows In-System Testing
  • Low Power Minimizes Self-Heating to Under 0.02°C

2 Applications

  • Automotive
  • Down Hole and Avionics

3 Description

The LM57-Q1 device is a precision, dual-output, temperature switch with analog temperature sensor output for wide temperature applications such as automotive grade. The trip temperature (TTRIP) is selected from 256 possible values in the range of –40°C to 160°C. The VTEMP is a class AB analog voltage output that is proportional to temperature with a programmable negative temperature coefficient (NTC). Two external 1% resistors set the TTRIP and VTEMP slope. The digital and analog outputs enable protection and monitoring of system thermal events.

Built-in thermal hysteresis (THYST) prevents the digital outputs from oscillating. The TOVER and TOVER digital outputs will assert when the die temperature exceeds TTRIP and will de-assert when the temperature falls below a temperature equal to TTRIP minus THYST.

TOVER is active-high with a push-pull structure. TOVER is active-low with an open-drain structure. Tying TOVER to TRIP-TEST will latch the output after it trips. The output can be cleared by forcing TRIP-TEST low. Driving the TRIP-TEST high will assert the digital outputs. A processor can check the state of TOVER or TOVER, confirming they changed to an active state. This allows for in situ verification that the comparator and output circuitry are functional after system assembly. When TRIP-TEST is high, the trip-level reference voltage appears at the VTEMP pin. The system could then use this voltage to calculate the threshold of the LM57-Q1.

Device Information (1)(2)

PART NUMBER PACKAGE BODY SIZE (NOM)
LM57 -Q1 TSSOP (8) 3.00 mm × 6.40 mm
  1. For all available packages, see the orderable addendum at the end of the data sheet.
  2. For device comparison see Device Comparison Table.

LM57-Q1 Overtemperature Alarm

LM57-Q1 30080576.gif

Temperature Transfer Function

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