SLVS782D November   2007  – October 2020 TPS2041B-Q1 , TPS2042B-Q1 , TPS2051B-Q1

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and 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 Parameter Measurement Information
  8. 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 (EN)
      6. 8.3.6 Overcurrent ( OCx)
      7. 8.3.7 Current Sense
      8. 8.3.8 Thermal Sense
      9. 8.3.9 Undervoltage Lockout (UVLO)
    4. 8.4 Device Functional Modes
  9. 9 Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 Universal Serial Bus (USB) Applications
    2. 9.2 Typical Applications
      1. 9.2.1 TPS2042B-Q1 Typical Application
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
          1. 9.2.1.2.1 Overcurrent
          2. 9.2.1.2.2 OC Response
        3. 9.2.1.3 Application Curves
      2. 9.2.2 Hosts and Self-Powered Hubs 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. 9.2.3 Generic Hot-Plug Applications
        1. 9.2.3.1 Design Requirements
        2. 9.2.3.2 Detailed Design Procedure
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
    3. 11.3 Thermal Considerations
  12. 12Device and Documentation Support
    1. 12.1 Related Links
    2. 12.2 Receiving Notification of Documentation Updates
    3. 12.3 Support Resources
    4. 12.4 Trademarks
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

11.3 Thermal Considerations

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 6-9. Using this value, the power dissipation per switch can be calculated by Equation 1:

Equation 1. 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 2:

Equation 2. 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.