SLVS514O April   2004  – June 2024 TPS2041B , TPS2042B , TPS2043B , TPS2044B , TPS2051B , TPS2052B , TPS2053B , TPS2054B

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 General Switch Catalog
  6. 5 Pin Configuration and Functions
  7. 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 (All Devices Excluding TPS2051BDBV and TPS2052BD)
    7. 6.7 Typical Characteristics (TPS2051BDBV and TPS2052BD)
  8. 7 Parameter Measurement Information
  9. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagrams
    3. 8.3 Feature Description
      1. 8.3.1  Power Switch
      2. 8.3.2  Charge Pump
      3. 8.3.3  Driver
      4. 8.3.4  Enable ( ENx)
      5. 8.3.5  Enable (ENx)
      6. 8.3.6  Current Sense
      7. 8.3.7  Overcurrent
        1. 8.3.7.1 Overcurrent Conditions (TPS20x3BD, TPS20x4BD, and TPS20x2BDRB)
        2. 8.3.7.2 Overcurrent Conditions (TPS20x1B & TPS20x2B in D, DGN, and DBV packages)
      8. 8.3.8  Overcurrent ( OCx)
      9. 8.3.9  Thermal Sense
      10. 8.3.10 Undervoltage Lockout
    4. 8.4 Device Functional Modes
  10. 9 Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 Universal Serial Bus (USB) Applications
    2. 9.2 Typical Application
      1. 9.2.1 Typical Application (TPS2042B)
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
          1. 9.2.1.2.1 Power-Supply Considerations
          2. 9.2.1.2.2 OC Response
        3. 9.2.1.3 Application Curves
      2. 9.2.2 Host and Self-Powered and Bus-Powered Hubs
        1. 9.2.2.1 Design Requirements
          1. 9.2.2.1.1 USB Power-Distribution Requirements
        2. 9.2.2.2 Detailed Design Procedure
          1. 9.2.2.2.1 Low-Power Bus-Powered and High-Power Bus-Powered Functions
        3. 9.2.2.3 Application Curves
      3. 9.2.3 Generic Hot-Plug Applications
        1. 9.2.3.1 Design Requirements
        2. 9.2.3.2 Detailed Design Procedure
        3. 9.2.3.3 Application Curves
  11. 10Power Supply Recommendations
    1. 10.1 Undervoltage Lockout (UVLO)
  12. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
    3. 11.3 Power Dissipation
    4. 11.4 Thermal Protection
  13. 12Device and Documentation Support
    1. 12.1 Receiving Notification of Documentation Updates
    2. 12.2 Support Resources
    3. 12.3 Trademarks
    4. 12.4 Electrostatic Discharge Caution
    5. 12.5 Glossary
  14. 13Revision History
  15. 14Mechanical, Packaging, and Orderable Information

Package Options

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

11.3 Power Dissipation

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 6-11. Using this value, the power dissipation per switch can be calculated by Equation :

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.

Finally, calculate the junction temperature with Equation :

TJ = PD × 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.