ZHCSDV7 July   2015 LM57-Q1

PRODUCTION DATA.  

  1. 1 特性
  2. 2 应用范围
  3. 3 说明
  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. 11器件和文档支持
    1. 11.1 文档支持
      1. 11.1.1 相关文档
    2. 11.2 社区资源
    3. 11.3 商标
    4. 11.4 静电放电警告
    5. 11.5 Glossary
  12. 12机械、封装和可订购信息

封装选项

机械数据 (封装 | 引脚)
散热焊盘机械数据 (封装 | 引脚)
订购信息

10 Layout

10.1 Layout Guidelines

The LM57-Q1 can be applied easily in the same way as other integrated-circuit temperature sensors. It can be glued or cemented to a surface. The temperatures of the lands and traces to the other leads of the LM57-Q1 will also affect the temperature reading.

Alternatively, the LM57-Q1 can be mounted inside a sealed-end metal tube, and can then be dipped into a bath or screwed into a threaded hole in a tank. As with any IC, the LM57-Q1 and accompanying wiring and circuits must be kept insulated and dry, to avoid leakage and corrosion. This is especially true if the circuit may operate at cold temperatures where condensation can occur. If moisture creates a short circuit from the VTEMP output to ground or VDD, the VTEMP output from the LM57-Q1 will not be correct. Printed-circuit coatings are often used to ensure that moisture cannot corrode the leads or circuit traces.

10.2 Layout Example

LM57-Q1 Layout01_SNIS152.gifFigure 25. PW (TSSOP) Package Layout Example

10.3 Temperature Considerations

The junction temperature of the LM57-Q1 is the actual temperature being measured. The thermal resistance junction-to-ambient (RθJA) is the parameter (from ) used to calculate the rise of a device junction temperature due to its power dissipation. Equation 3 is used to calculate the rise in the die temperature of the LM57-Q1.

Equation 3. LM57-Q1 30080512.gif

where

  • TA is the ambient temperature.
  • IQ is the quiescent current.
  • IL is the load current on VTEMP.
  • RθJA can be found in

For example using an LM57-Q1 in the PW (TSSOP) package, in an application where TA = 30°C, VDD = 5.5 V, IDD = 28 μA, J5 gain, VTEMP = 2368 mV, and IL = 0 μA, the total temperature rise would be [183°C/W × 5.5 V × 28 μA] = 0.028°C. To minimize self-heating, the load current on VTEMP should be minimized.