SLVSBF8C March   2013  – May 2015 TPS82692 , TPS82693 , TPS826951 , TPS82697 , TPS82698

PRODUCTION DATA.  

  1. Features
  2. Applications
  3. Description
    1.     Device Images
      1.      Simplified Schematic
      2.      Efficiency vs Output Current
  4. Revision History
  5. Device Comparison
  6. Pin Configuration and Functions
    1.     Pin 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 Electrical Characteristics
    6. 7.6 Typical Characteristics
  8. Parameter Measurement Information
  9. Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1 Power-Save Mode
      2. 9.3.2 Mode Selection
      3. 9.3.3 Soft Start
    4. 9.4 Device Functional Modes
      1. 9.4.1 Low Dropout, 100% Duty Cycle Operation
      2. 9.4.2 Enable
  10. 10Application and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Application
      1. 10.2.1 Input Capacitor Selection
      2. 10.2.2 Output Capacitor Selection
  11. 11Power Supply Recommendations
  12. 12Layout
    1. 12.1 Layout Guidelines
    2. 12.2 Layout Example
    3. 12.3 Surface Mount Information
    4. 12.4 Thermal And Reliability Information
    5. 12.5 Package Summary
      1.      SIP Package
    6. 12.6 MicroSIP
  13. 13Device and Documentation Support
    1. 13.1 Documentation Support
      1. 13.1.1 Related Documentation
    2. 13.2 Related Links
    3. 13.3 Trademarks
    4. 13.4 Electrostatic Discharge Caution
    5. 13.5 Glossary
  14. 14Mechanical, Packaging, and Orderable Information
    1. 14.1 Tape and Reel Information

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Thermal And Reliability Information

The TPS8269x output current may need to be de-rated if it is required to operate in a high ambient temperature or deliver a large amount of continuous power. The amount of current de-rating is dependent upon the input voltage, output power and environmental thermal conditions. Care should especially be taken in applications where the localized PWB temperature exceeds 65°C.

The TPS8269x die and inductor temperature should be kept lower than the maximum rating of 125°C, so care should be taken in the circuit layout to ensure good heat sinking. Sufficient cooling should be provided to ensure reliable operation.

Three basic approaches for enhancing thermal performance are listed below:

  • Improve the power dissipation capability of the PCB design.
  • Improve the thermal coupling of the component to the PCB.
  • Introduce airflow into the system.

To estimate the junction temperature, approximate the power dissipation within the TPS8269x by applying the typical efficiency stated in this datasheet to the desired output power; or, by taking a power measurement if you have an actual TPS8269x device or a TPS8269x evaluation module. Then calculate the internal temperature rise of the TPS8269x above the surface of the printed circuit board by multiplying the TPS8269x power dissipation by the thermal resistance.

The thermal resistance numbers listed in the Thermal Information table are based on modeling the MicroSIP™ package mounted on a high-K test board specified per JEDEC standard. For increased accuracy and fidelity to the actual application, it is recommended to run a thermal image analysis of the actual system. Figure 46 and Figure 47 are thermal images of TI’s evaluation board with readings of the temperatures at specific locations on the device.

TPS82692 TPS82693 TPS826951 TPS82697 TPS82698 thermal_plot_400mA.gifFigure 46. V=3.6v, V=2.85v, I=400ma 80mw Power Dissipation At Room Temp.INOUTOUT
TPS82692 TPS82693 TPS826951 TPS82697 TPS82698 thermal_plot_900mA.gifFigure 47. V=3.6v, V=2.85v, I=800ma 330mw Power Dissipation At Room Temp.INOUTOUT

The TPS8269x is equipped with a thermal shutdown that will inhibit power switching at high junction temperatures. The activation threshold of this function, however, is above 125°C to avoid interfering with normal operation. Thus, it follows that prolonged or repetitive operation under a condition in which the thermal shutdown activates necessarily means that the components internal to the MicroSIP package are subjected to high temperatures for prolonged or repetitive intervals, which may damage or impair the reliability of the device.

MLCC capacitor reliability/lifetime is depending on temperature and applied voltage conditions. At higher temperatures, MLCC capacitors are subject to stronger stress. On the basis of frequently evaluated failure rates determined at standardized test conditions, the reliability of all MLCC capacitors can be calculated for their actual operating temperature and voltage.

TPS82692 TPS82693 TPS826951 TPS82697 TPS82698 Capacitor_Guaranted_Lifetime_SLVSAZ9.pngFigure 48. Capacitor Lifetime vs Capacitor Case Temperature
TPS82692 TPS82693 TPS826951 TPS82697 TPS82698 Capacitor_B1Lifetime_SLVSAZ9.pngFigure 49. Capacitor B1 Lifetime vs Capacitor Case Temperature

Failures caused by systematic degradation can be described by the Arrhenius model. The most critical parameter (IR) is the Insulation Resistance (i.e. leakage current). The drop of IR below a lower limit (e.g., 1 MΩ) is used as the failure criterion, see Figure 48. Figure 49 (B1 life) defines the capacitor lifetime based on a failure rate reaching 1%. Note that the wear-out mechanisms occurring in the MLCC capacitors are not reversible but cumulative over time.