SLLSEO6C June   2015  – August 2018 TUSB321


  1. Features
  2. Applications
  3. Description
    1.     Device Images
      1.      Simplified Schematic
      2.      Sample Applications
  4. Revision History
  5. Pin Configuration and Functions
    1.     Pin Functions
  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 Switching Characteristics
  7. Detailed Description
    1. 7.1 Overview
      1. 7.1.1 Cables, Adapters, and Direct Connect Devices
        1. USB Type-C Receptacles and Plugs
        2. USB Type-C Cables
        3. Legacy Cables and Adapters
        4. Direct Connect Devices
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Port Role Configuration
        1. Downstream Facing Port (DFP) - Source
        2. Upstream Facing Port (UFP) - Sink
        3. Dual Role Port (DRP)
      2. 7.3.2 Type-C Current Mode
      3. 7.3.3 VBUS Detection
      4. 7.3.4 Cable Orientation and External MUX Control
      5. 7.3.5 VCONN Support for Active Cables
    4. 7.4 Device Functional Modes
      1. 7.4.1 Unattached Mode
      2. 7.4.2 Active Mode
  8. Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 DFP Mode
        1. Design Requirements
        2. Detailed Design Procedure
        3. Application Curve
    3. 8.3 Initialization Set Up
  9. Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Receiving Notification of Documentation Updates
    2. 11.2 Community Resources
    3. 11.3 Trademarks
    4. 11.4 Electrostatic Discharge Caution
    5. 11.5 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

Detailed Design Procedure

The TUSB321 device supports a VDD in the range of 4.5 to 5.5 V. In this particular case, VDD is set to 5 V. A 100-nF capacitor is placed near VDD. Also, a 100 µF is used to meet the USB Type-C bulk capacitance requirement of 10 µF to 220 µF.

The TUSB321 current advertisement is determined by the state of the CURRENT_MODE pin. In this particular example, 3.0 A advertisement is desired so the CURRENT_MODE pin is pulled high to VDD through 10-kΩ resistor.

The DIR pin is used to control the MUX for connecting the USB3 SS signals to the appropriate pins on the USB Type-C receptacle. In this particular case, a HD3SS3212 is used as the MUX. In order to minimize crossing in routing the USB3 SS signals to the USB Type C connector, the connection of CC1 and CC2 to the TUSB321 is swapped.

The Type-C port mode is determined by the state of the PORT pin. When the PORT pin is pulled high, the TUSB321 device is in DFP mode.

The VBUS_DET pin must be connected through a RVBUS resistor to VBUS on the Type-C that is connected. This large resistor is required to protect the TUSB321 device from large VBUS voltage that is possible in present day systems. This resistor along with internal pulldown keeps the voltage observed by the TUSB321 device in the recommended range.

The USB2 specification requires the bulk capacitance on VBUS based on UFP or DFP. When operating the TUSB321 device in a DFP mode, a bulk capacitance of at least 120 µF is required. In this particular case, a 150-µF capacitor was chosen.