SLVS490J december   2003  – august 2023 TPS2061 , TPS2062 , TPS2063 , TPS2065 , TPS2066 , TPS2067

PRODMIX  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Revision History
  6. 5 Description (continued)
  7. 6 Pin Configuration and Functions
  8. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 Dissipating Rating Table
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Electrical Characteristics
    5. 7.5 Typical Characteristics(All Devices Excluding TPS2065DBV)
    6. 7.6 Typical Characteristics (TPS2065DBV)
  9. 8 Parameter Measurement Information
  10. 9 Detailed Description
    1. 9.1  Functional Block Diagram
    2. 9.2  Power Switch
    3. 9.3  Charge Pump
    4. 9.4  Driver
    5. 9.5  Enable ( ENx or ENx)
    6. 9.6  Current Sense
    7. 9.7  Overcurrent
      1. 9.7.1 Overcurrent Conditions (All Devices Excluding TPS2065DBV)
      2. 9.7.2 Overcurrent Conditions (TPS2065DBV)
    8. 9.8  Overcurrent ( OCx)
    9. 9.9  Thermal Sense
    10. 9.10 Undervoltage Lockout
  11. 10Application and Implementation
    1. 10.1 Application Information
      1. 10.1.1  Power-supply Considerations
      2. 10.1.2  OC Response
      3. 10.1.3  Power Dissipation and Junction Temperature
      4. 10.1.4  Thermal Protection
      5. 10.1.5  Undervoltage Lockout (UVLO)
      6. 10.1.6  Universal Serial Bus (USB) Applications
      7. 10.1.7  Host/Self-Powered and Bus-powered Hubs
      8. 10.1.8  Low-power Bus-powered and High-Power Bus-Powered Functions
      9. 10.1.9  USB Power-distribution Requirements
      10. 10.1.10 Generic Hot-Plug Applications
  12. 11Device and Documentation Support
    1. 11.1 Device Support
    2. 11.2 Documentation Support
    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
  13. 12Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • D|8
  • DBV|5
  • DGN|8
Thermal pad, mechanical data (Package|Pins)
Orderable Information

10.1.3 Power Dissipation and Junction Temperature

The low on-resistance on the N-channel MOSFET allows the small surface-mount packages to pass large currents. The thermal resistances of these packages are high compared to those of power packages; it is good design practice to check power dissipation and junction temperature. Begin by determining the rDS(on) of the N-channel MOSFET relative to the input voltage and operating temperature. As an initial estimate, use the highest operating ambient temperature of interest and read rDS(on) from Figure 7-11. Using this value, the power dissipation per switch can be calculated by:

  • PD = rDS(on)× I2

Multiply this number by the number of switches being used. This step renders the total power dissipation from the N-channel MOSFETs.

The thermal resistance, RθJA = 1 / (DERATING FACTOR), where DERATING FACTOR is obtained from the Dissipation Ratings Table. Thermal resistance is a strong function of the printed circuit board construction , and the copper trace area connecting the integrated circuit.

Finally, calculate the junction temperature:

  • TJ = PD x RθJA + TA

Where:

  • TA= Ambient temperature °C
  • RθJA = Thermal resistance
  • PD = Total power dissipation based on number of switches being used.

Compare the calculated junction temperature with the initial estimate. If they do not agree within a few degrees, repeat the calculation, using the calculated value as the new estimate. Two or three iterations are generally sufficient to get a reasonable answer.