SLVS514M June   2010  – June 2016 TPS2041B , TPS2042B , TPS2043B , TPS2044B , TPS2051B , TPS2052B , TPS2053B , TPS2054B

PRODUCTION DATA.  

  1. Features
  2. Applications
  3. Description
  4. Revision History
  5. General Switch Catalog
  6. Pin Configuration and 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 Dissipation Ratings
    7. 7.7 Typical Characteristics
  8. Parameter Measurement Information
  9. Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagrams
    3. 9.3 Feature Description
      1. 9.3.1 Power Switch
      2. 9.3.2 Charge Pump
      3. 9.3.3 Driver
      4. 9.3.4 Enable (ENx)
      5. 9.3.5 Enable (ENx)
      6. 9.3.6 Overcurrent (OCx)
      7. 9.3.7 Current Sense
      8. 9.3.8 Thermal Sense
      9. 9.3.9 Undervoltage Lockout
    4. 9.4 Device Functional Modes
  10. 10Application and Implementation
    1. 10.1 Application Information
      1. 10.1.1 Universal Serial Bus (USB) Applications
    2. 10.2 Typical Application
      1. 10.2.1 Typical Application (TPS2042B)
        1. 10.2.1.1 Design Requirements
        2. 10.2.1.2 Detailed Design Procedure
          1. 10.2.1.2.1 Power-Supply Considerations
          2. 10.2.1.2.2 Overcurrent
          3. 10.2.1.2.3 OC Response
        3. 10.2.1.3 Application Curves
      2. 10.2.2 Host and Self-Powered and Bus-Powered Hubs
        1. 10.2.2.1 Design Requirements
          1. 10.2.2.1.1 USB Power-Distribution Requirements
        2. 10.2.2.2 Detailed Design Procedure
          1. 10.2.2.2.1 Low-Power Bus-Powered and High-Power Bus-Powered Functions
        3. 10.2.2.3 Application Curves
      3. 10.2.3 Generic Hot-Plug Applications
        1. 10.2.3.1 Design Requirements
        2. 10.2.3.2 Detailed Design Procedure
        3. 10.2.3.3 Application Curves
  11. 11Power Supply Recommendations
    1. 11.1 Undervoltage Lockout (UVLO)
  12. 12Layout
    1. 12.1 Layout Guidelines
    2. 12.2 Layout Example
    3. 12.3 Power Dissipation
    4. 12.4 Thermal Protection
  13. 13Device and Documentation Support
    1. 13.1 Receiving Notification of Documentation Updates
    2. 13.2 Related Links
    3. 13.3 Community Resources
    4. 13.4 Trademarks
    5. 13.5 Electrostatic Discharge Caution
    6. 13.6 Glossary
  14. 14Mechanical, Packaging, and Orderable Information

Package Options

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

Layout

Layout Guidelines

  • Place the 100-nF bypass capacitor near the IN and GND pins, and make the connections using a low-inductance trace.
  • Placing a high-value electrolytic capacitor and a 100-nF bypass capacitor on the output pin is recommended when large transient currents are expected on the output.
  • The PowerPAD should be directly connected to PCB ground plane using wide and short copper trace.

Layout Example

TPS2041B TPS2042B TPS2043B TPS2044B TPS2051B TPS2052B TPS2053B TPS2054B TPS2042.png Figure 66. Layout Recommendation

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 13. 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.

Finally, calculate the junction temperature with :

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.

Thermal Protection

Thermal protection prevents damage to the IC when heavy-overload or short-circuit faults are present for extended periods of time. The TPS20xxB implements a thermal sensing to monitor the operating junction temperature of the power distribution switch. In an overcurrent or short-circuit condition, the junction temperature rises due to excessive power dissipation. Once the die temperature rises to approximately 140°C due to overcurrent conditions, the internal thermal sense circuitry turns the power switch off, thus preventing the power switch from damage. Hysteresis is built into the thermal sense circuit, and after the device has cooled approximately 10°C, the switch turns back on. The switch continues to cycle in this manner until the load fault or input power is removed. The OCx open-drain output is asserted (active low) when an overtemperature shutdown or overcurrent occurs.