SBVS067R January   2006  – December 2019 TPS737

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Typical Application Circuit
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin 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 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagrams
    3. 7.3 Feature Description
      1. 7.3.1 Output Noise
      2. 7.3.2 Internal Current Limit
      3. 7.3.3 Enable Pin and Shutdown
      4. 7.3.4 Reverse Current
    4. 7.4 Device Functional Modes
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Input and Output Capacitor Requirements
        2. 8.2.2.2 Dropout Voltage
        3. 8.2.2.3 Transient Response
      3. 8.2.3 Application Curves
    3. 8.3 What To Do and What Not To Do
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
      1. 10.1.1 Power Dissipation
      2. 10.1.2 Thermal Protection
      3. 10.1.3 Estimating Junction Temperature
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Development Support
        1. 11.1.1.1 Evaluation Modules
        2. 11.1.1.2 Spice Models
      2. 11.1.2 Device Nomenclature
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 Receiving Notification of Documentation Updates
    4. 11.4 Support Resources
    5. 11.5 Trademarks
    6. 11.6 Electrostatic Discharge Caution
    7. 11.7 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

10.1.3 Estimating Junction Temperature

Using the thermal metrics ΨJT and ΨJB, as shown in the Thermal Information table, the junction temperature can be estimated with corresponding formulas (given in Equation 8). For backward compatibility, an older θJC,Top parameter is listed as well.

Equation 8. TPS737 q_new_metrics_bvs066.gif

Where PD is the power dissipation shown by Equation 6, TT is the temperature at the center-top of the IC package, and TB is the PCB temperature measured 1-mm away from the IC package on the PCB surface (as Figure 38 shows).

NOTE

Both TT and TB can be measured on actual application boards using a thermo‐gun (an infrared thermometer).

For more information about measuring TT and TB, see the application note, Using New Thermal Metrics (SBVA025), available for download at www.ti.com.

By looking at Figure 37, the new thermal metrics (ΨJT and ΨJB) have very little dependency on board size. That is, using ΨJT or ΨJB with Equation 8 is a good way to estimate TJ by simply measuring TT or TB, regardless of the application board size.

TPS737 ai_psi_jt_jb_bvs067.gifFigure 37. ΨJT and ΨJB vs Board Size

For a more detailed discussion of why TI does not recommend using θJC(top) to determine thermal characteristics, refer to application report, Using New Thermal Metrics (SBVA025), available for download at www.ti.com. For further information, refer to application report, IC Package Thermal Metrics (SPRA953), also available on the TI website.

TPS737 ai_thermal_measmt_bvs067.gif
1. Power dissipation may limit operating range. Check Thermal Information table.
Figure 38. Measuring Points for TT and TB