SBVS067U January   2006  – September 2024 TPS737

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Thermal Information
    5. 5.5 Thermal Information
    6. 5.6 Electrical Characteristics
    7. 5.7 Typical Characteristics
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagrams
    3. 6.3 Feature Description
      1. 6.3.1 Output Noise
      2. 6.3.2 Internal Current Limit
      3. 6.3.3 Enable Pin and Shutdown
      4. 6.3.4 Reverse Current
    4. 6.4 Device Functional Modes
  8. 7 Application and Implementation
    1. 7.1 Application Information
    2. 7.2 Typical Application
      1. 7.2.1 Design Requirements
      2. 7.2.2 Detailed Design Procedure
        1. 7.2.2.1 Input and Output Capacitor Requirements
        2. 7.2.2.2 Dropout Voltage
        3. 7.2.2.3 Transient Response
      3. 7.2.3 Application Curves
    3. 7.3 Best Design Practices
    4. 7.4 Power Supply Recommendations
    5. 7.5 Layout
      1. 7.5.1 Layout Guidelines
        1. 7.5.1.1 Power Dissipation
        2. 7.5.1.2 Thermal Protection
        3. 7.5.1.3 Estimating Junction Temperature
      2. 7.5.2 Layout Example
  9. 8 Device and Documentation Support
    1. 8.1 Device Support
      1. 8.1.1 Development Support
        1. 8.1.1.1 Evaluation Modules
        2. 8.1.1.2 Spice Models
      2. 8.1.2 Device Nomenclature
    2. 8.2 Documentation Support
      1. 8.2.1 Related Documentation
    3. 8.3 Receiving Notification of Documentation Updates
    4. 8.4 Support Resources
    5. 8.5 Trademarks
    6. 8.6 Electrostatic Discharge Caution
    7. 8.7 Glossary
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information

7.5.1.1 Power Dissipation

Knowing the device power dissipation and proper sizing of the thermal plane that is connected to the tab or pad is critical to avoiding thermal shutdown and to provide reliable operation.

Power dissipation of the device depends on input voltage and load conditions and can be calculated using Equation 6:

Equation 6. TPS737

Power dissipation can be minimized and greater efficiency can be achieved by using the lowest possible input voltage necessary to achieve the required output voltage regulation.

On both the VSON (DRB) and WSON (DRV) packages, the primary conduction path for heat is through the exposed pad to the printed circuit board (PCB). The pad can be connected to ground or left floating; however, the pad must be attached to an appropriate amount of copper PCB area to make sure the device does not overheat. On the SOT-223 (DCQ) package, the primary conduction path for heat is through the tab to the PCB. That tab must be connected to ground. The maximum junction-to-ambient thermal resistance depends on the maximum ambient temperature, maximum device junction temperature, and power dissipation of the device and can be calculated using Equation 7:

Equation 7. TPS737

Knowing the maximum RθJA, the minimum amount of PCB copper area needed for appropriate heat sinking can be estimated using Figure 7-9.

TPS737 RθJA vs Board Size
RθJA value at board size of 9 in2 (that is, 3 in × 3 in) is a JEDEC standard.
Figure 7-9 RθJA vs Board Size

Figure 7-9 shows the variation of RθJA as a function of ground plane copper area in the board. Figure 7-9 is intended only as a guideline to demonstrate the effects of heat spreading in the ground plane and is not intended to be used to estimate actual thermal performance in real application environments.

Note:

When the device is mounted on an application PCB, use ΨJT and ΨJB, as explained in the Thermal Information table.