SLLSFC5C November   2021  – January 2023 ISOUSB211

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Revision History
  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  Power Ratings
    6. 6.6  Insulation Specifications
    7. 6.7  Safety-Related Certifications
    8. 6.8  Safety Limiting Values
    9. 6.9  Electrical Characteristics
    10. 6.10 Switching Characteristics
    11. 6.11 Insulation Characteristics Curves
    12. 6.12 Typical Characteristics
  8. 7 Parameter Measurement Information
    1. 7.1 Test Circuits
  9. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1  Power Supply Options
      2. 8.3.2  Power Up
      3. 8.3.3  Symmetric Operation, Dual-Role Port and Role-Reversal
      4. 8.3.4  Connect and Speed Detection
      5. 8.3.5  Disconnect Detection
      6. 8.3.6  Reset
      7. 8.3.7  LS/FS Message Traffic
      8. 8.3.8  HS Message Traffic
      9. 8.3.9  Equalization and Pre-emphasis
      10. 8.3.10 L2 Power Management State (Suspend) and Resume
      11. 8.3.11 L1 Power Management State (Sleep) and Resume
      12. 8.3.12 HS Test Mode Support
      13. 8.3.13 CDP Advertising
    4. 8.4 Device Functional Modes
  10. 9 Power Supply Recommendations
  11. 10Application and Implementation
    1. 10.1 Typical Application
      1. 10.1.1 Isolated Host or Hub
      2. 10.1.2 Isolated Peripheral - Self-Powered
      3. 10.1.3 Isolated Peripheral - Bus-Powered
      4. 10.1.4 Application Curve
        1. 10.1.4.1 Insulation Lifetime
    2. 10.2 Meeting USB2.0 HS Eye-Diagram Specifications
    3. 10.3 Thermal Considerations
      1. 10.3.1 VBUS / V3P3V Power
      2. 10.3.2 VCCx / V1P8Vx Power
      3. 10.3.3 Example Configuration 1
      4. 10.3.4 Example Configuration 2
      5. 10.3.5 Example Configuration 3
  12. 11Layout
    1. 11.1 Layout Guidelines
      1. 11.1.1 Layout Example
      2. 11.1.2 PCB Material
  13. 12Device and Documentation Support
    1. 12.1 Documentation Support
      1. 12.1.1 Related Documentation
    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
  14. 13Mechanical, Packaging, and Orderable Information
    1. 13.1 Tape and Reel Information

Package Options

Mechanical Data (Package|Pins)
  • DP|28
Thermal pad, mechanical data (Package|Pins)
Orderable Information

8.3.1 Power Supply Options

The ISOUSB211 can be powered by connecting a 4.25 V to 5.5 V supply on VBUSx pins, in which case an internal LDO generates V3P3Vx voltage. This option is suitable for the side facing the USB connector, where a 5-V VBUS supply is available. Alternatively, VBUSx and V3P3Vx pins can be shorted together and an external 3.3-V power supply can be connected to both. This second option is suitable for the side facing the microcontroller, where a 5-V supply may not be available.

The ISOUSB211 also needs a 1.8-V supply for operation. A 2.4 V to 5.5 V supply can be connected on VCCx pins, in which case internal LDOs generate the V1P8Vx supplies. In the simplest implementation, VCCx can be connected to the USB VBUS on the side facing the connector, and to the 3.3-V local supply on the side facing the microcontroller. In this implementation, there is power dissipation on the internal LDOs of ISOUSB, which limits the maximum ambient temperature supported by ISOUSB211.

To reduce power dissipation inside the ISOUSB211, an external 1.8-V supply can be connected to both VCCx and V1P8Vx pins shorted together, in which case the internal 1.8-V LDOs of ISOUSB211 are bypassed. In this implementation, some of the power dissipation is transferred to the external 1.8-V supply, and overall higher ambient temperature operation is achieved for the ISOUSB211. If the external 1.8-V supply is an LDO, the effect is to reduce power dissipation inside ISOUSB211, but overall no reduction in system current or power dissipation is achieved. Alternatively, if the external 1.8-V supply is a DC-DC (buck) converter, both system power and ISOUSB211 power dissipation can be reduced.

A third option is to include external resistors between VCCx pins and VBUS and 3.3-V local supplies. These resistors can be accomodated since VCCx pins operate down to 2.4 V. The resistors drop voltage and dissipate power and serve a similar purpose as external 1.8-V LDOs, that is, reduce power dissipation inside ISOUSB211 and allow higher ambient temperature operation.

Refer to the Thermal Considerations section for further details on how to optimize ISOUSB211 internal power dissipation according to the maximum ambient temperature required in the system, and for recommendations on external resistors, LDOs and buck converters.