SLLS505P February   2002  – February 2022 SN65HVD10 , SN65HVD11 , SN65HVD12 , SN75HVD10 , SN75HVD11 , SN75HVD12


  1. Features
  2. Applications
  3. Description
  4. Revision History
  5. Device Comparison Table
  6. Pin Configuration and Functions
  7. Specifications
    1. 7.1  Absolute Maximum Ratings
    2. 7.2  ESD Ratings
    3. 7.3  Recommended Operating Conditions
    4. 7.4  Thermal Information
    5. 7.5  Driver Electrical Characteristics
    6. 7.6  Receiver Electrical Characteristics
    7. 7.7  Power Dissipation Characteristics
    8. 7.8  Driver Switching Characteristics
    9. 7.9  Receiver Switching Characteristics
    10. 7.10 Dissipation Ratings
    11. 7.11 Typical Characteristics
  8. Parameter Measurement Information
  9. Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
    4. 9.4 Device Functional Modes
      1. 9.4.1 Low-Power Standby Mode
  10. 10Application and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Application
      1. 10.2.1 Design Requirements
        1. Data Rate and Bus Length
        2. Stub Length
        3. Bus Loading
        4. Receiver Fail-safe
      2. 10.2.2 Detailed Design Procedure
      3. 10.2.3 Application Curve
  11. 11Power Supply Recommendations
  12. 12Layout
    1. 12.1 Layout Guidelines
    2. 12.2 Layout Example
    3. 12.3 Thermal Considerations
      1. 12.3.1 Thermal Characteristics of IC Packages
  13. 13Device and Documentation Support
    1. 13.1 Device Support
    2. 13.2 Related Links
    3. 13.3 Receiving Notification of Documentation Updates
    4. 13.4 Support Resources
    5. 13.5 Trademarks
    6. 13.6 Electrostatic Discharge Caution
    7. 13.7 Glossary
  14. 14Mechanical, Packaging, and Orderable Information

Package Options

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

Thermal Characteristics of IC Packages

RθJA (Junction-to-Ambient Thermal Resistance) is defined as the difference in junction temperature to ambient temperature divided by the operating power.

RθJA is not a constant and is a strong function of:

  • the PCB design (50% variation)
  • altitude (20% variation)
  • device power (5% variation)

RθJA can be used to compare the thermal performance of packages when specific test conditions are defined and used. Standardized testing includes specification of PCB construction, test chamber volume, sensor locations, and the thermal characteristics of holding fixtures. RθJA is often misused when it is used to calculate junction temperatures for other installations.

TI uses two test PCBs as defined by JEDEC specifications. The low-k board gives average in-use condition thermal performance, and it consists of a single copper trace layer 25 mm long and 2-oz thick. The high-k board gives best case in-use condition, and it consists of two 1-oz buried power planes with a single copper trace layer 25 mm long and 2-oz thick. A 4% to 50% difference in RθJA can be measured between these two test cards.

RθJC (Junction-to-Case Thermal Resistance) is defined as the difference in junction temperature to case divided by the operating power. It is measured by putting the mounted package up against a copper block cold plate to force heat to flow from the die, through the mold compound into the copper block.

RθJC is a useful thermal characteristic when a heat sink is applied to package. It is not a useful characteristic to predict junction temperature, because it provides pessimistic numbers if the case temperature is measured in a nonstandard system and junction temperatures are backed out. It can be used with RθJB in 1-dimensional thermal simulation of a package system.

RθJB (Junction-to-Board Thermal Resistance) is defined as the difference in the junction temperature and the PCB temperature at the center of the package (closest to the die) when the PCB is clamped in a cold-plate structure. RθJB is only defined for the high-k test card.

RθJB provides an overall thermal resistance between the die and the PCB. It includes a bit of the PCB thermal resistance (especially for BGAs with thermal balls) and can be used for simple 1-dimensional network analysis of package system, see Figure 12-2.

GUID-4D6263C9-E104-4839-A350-4E81108CAEBB-low.gifFigure 12-2 PCB Thermal Resistances