SLLSEE4E June   2014  – June 2016 TUSB8041

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Description (Continued)
  6. 6 Pin Configuration and Functions
  7. 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, 3.3-V I/O
    6. 7.6 Timing Requirements, Power-Up
    7. 7.7 Hub Input Supply Current
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Battery Charging Features
      2. 8.3.2 USB Power Management
      3. 8.3.3 One Time Programmable (OTP) Configuration
      4. 8.3.4 Clock Generation
      5. 8.3.5 Crystal Requirements
      6. 8.3.6 Input Clock Requirements
      7. 8.3.7 Power-Up and Reset
    4. 8.4 Device Functional Modes
      1. 8.4.1 External Configuration Interface
      2. 8.4.2 I2C EEPROM Operation
      3. 8.4.3 SMBus Slave Operation
    5. 8.5 Register Maps
      1. 8.5.1  Configuration Registers
      2. 8.5.2  ROM Signature Register
      3. 8.5.3  Vendor ID LSB Register
      4. 8.5.4  Vendor ID MSB Register
      5. 8.5.5  Product ID LSB Register
      6. 8.5.6  Product ID MSB Register
      7. 8.5.7  Device Configuration Register
      8. 8.5.8  Battery Charging Support Register
      9. 8.5.9  Device Removable Configuration Register
      10. 8.5.10 Port Used Configuration Register
      11. 8.5.11 Device Configuration Register 2
      12. 8.5.12 USB 2.0 Port Polarity Control Register
      13. 8.5.13 UUID Registers
      14. 8.5.14 Language ID LSB Register
      15. 8.5.15 Language ID MSB Register
      16. 8.5.16 Serial Number String Length Register
      17. 8.5.17 Manufacturer String Length Register
      18. 8.5.18 Product String Length Register
      19. 8.5.19 Serial Number String Registers
      20. 8.5.20 Manufacturer String Registers
      21. 8.5.21 Product String Registers
      22. 8.5.22 Additional Feature Configuration Register
      23. 8.5.23 Device Status and Command Register
  9. 9 Applications and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Discrete USB Hub Product
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
          1. 9.2.1.2.1 Upstream Port Implementation
          2. 9.2.1.2.2 Downstream Port 1 Implementation
          3. 9.2.1.2.3 Downstream Port 2 Implementation
          4. 9.2.1.2.4 Downstream Port 3 Implementation
          5. 9.2.1.2.5 Downstream Port 4 Implementation
          6. 9.2.1.2.6 VBUS Power Switch Implementation
          7. 9.2.1.2.7 Clock, Reset, and Misc
          8. 9.2.1.2.8 TUSB8041 Power Implementation
        3. 9.2.1.3 Application Curves
  10. 10Power Supply Recommendations
    1. 10.1 TUSB8041 Power Supply
    2. 10.2 Downstream Port Power
    3. 10.3 Ground
  11. 11Layout
    1. 11.1 Layout Guidelines
      1. 11.1.1 Placement
      2. 11.1.2 Package Specific
      3. 11.1.3 Differential Pairs
    2. 11.2 Layout Examples
      1. 11.2.1 Upstream Port
      2. 11.2.2 Downstream Port
  12. 12Device and Documentation Support
    1. 12.1 Community Resources
    2. 12.2 Trademarks
    3. 12.3 Electrostatic Discharge Caution
    4. 12.4 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

10 Power Supply Recommendations

10.1 TUSB8041 Power Supply

VDD should be implemented as a single power plane, as should VDD33.

  • The VDD pins of the TUSB8041 supply 1.1 V (nominal) power to the core of the TUSB8041. This power rail can be isolated from all other power rails by a ferrite bead to reduce noise.
  • The DC resistance of the ferrite bead on the core power rail can affect the voltage provided to the device due to the high current draw on the power rail. The output of the core voltage regulator may need to be adjusted to account for this or a ferrite bead with low DC resistance (less than 0.05 Ω) can be selected.
  • The VDD33 pins of the TUSB8041 supply 3.3 V power rail to the I/O of the TUSB8041. This power rail can be isolated from all other power rails by a ferrite bead to reduce noise.
  • All power rails require a 10 µF capacitor or 1 µF capacitors for stability and noise immunity. These bulk capacitors can be placed anywhere on the power rail. The smaller decoupling capacitors should be placed as close to the TUSB8041 power pins as possible with an optimal grouping of two of differing values per pin.

10.2 Downstream Port Power

  • The downstream port power, VBUS, must be supplied by a source capable of supplying 5V and up to 900 mA per port. Downstream port power switches can be controlled by the TUSB8041 signals. It is also possible to leave the downstream port power always enabled.
  • A large bulk low-ESR capacitor of 22 µF or larger is required on each downstream port’s VBUS to limit in-rush current.
  • The ferrite beads on the VBUS pins of the downstream USB port connections are recommended for both ESD and EMI reasons. A 0.1µF capacitor on the USB connector side of the ferrite provides a low impedance path to ground for fast rise time ESD current that might have coupled onto the VBUS trace from the cable.

10.3 Ground

It is recommended that only one board ground plane be used in the design. This provides the best image plane for signal traces running above the plane. The thermal pad of the TUSB8041 and any of the voltage regulators should be connected to this plane with vias. An earth or chassis ground is implemented only near the USB port connectors on a different plane for EMI and ESD purposes.