SLLSFL2A April   2022  – May 2024 TUSB1142

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1  Absolute Maximum Ratings
    2. 5.2  ESD Ratings
    3. 5.3  Recommended Operating Conditions
    4. 5.4  Thermal Information
    5. 5.5  Power Supply Characteristics
    6. 5.6  Control I/O DC Electrical Characteristics
    7. 5.7  USB Electrical Characteristics
    8. 5.8  Timing Requirements
    9. 5.9  Switching Characteristics
    10. 5.10 Typical Characteristics
  7. 6 Parameter Measurement Information
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 4-Level Inputs
      2. 7.3.2 USB Receiver Linear Equalization
        1. 7.3.2.1 Linear EQ Configuration
        2. 7.3.2.2 Full Adaptive Equalization
        3. 7.3.2.3 Fast Adaptive Equalization
      3. 7.3.3 USB Transmitter
        1. 7.3.3.1 Linearity VOD
        2. 7.3.3.2 Limited VOD
        3. 7.3.3.3 Transmit Equalization (Limited Redriver Mode Only)
      4. 7.3.4 USB 3.2 2:1 MUX Description
      5. 7.3.5 USB Polarity Inversion
      6. 7.3.6 Receiver Detect Control
    4. 7.4 Device Functional Modes
      1. 7.4.1 MODE Pin
      2. 7.4.2 Rx EQ Configuration in Pin-Strap Mode
      3. 7.4.3 USB 3.2 Power States
      4. 7.4.4 Disabling U1 and U2
    5. 7.5 Programming
      1. 7.5.1 Pseudocode Examples
        1. 7.5.1.1 Fixed EQ with Linear Redriver Mode
        2. 7.5.1.2 Fixed EQ with Limited Redriver Mode
        3. 7.5.1.3 Fast AEQ with Linear Redriver Mode
        4. 7.5.1.4 Fast AEQ with Limited Redriver Mode
        5. 7.5.1.5 Full AEQ with Linear Redriver Mode
        6. 7.5.1.6 Full AEQ with Limited Redriver Mode
      2. 7.5.2 TUSB1142 I2C Address Options
      3. 7.5.3 TUSB1142 I2C Target Behavior
    6. 7.6 Register Map
      1. 7.6.1 TUSB1142 Registers
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 USB SSTX Receiver Configuration
        2. 8.2.2.2 USB CRX1/2 Receiver Configuration
          1. 8.2.2.2.1 Fixed Equalization
          2. 8.2.2.2.2 Full Adaptive Equalization
          3. 8.2.2.2.3 Fast Adaptive Equalization
        3. 8.2.2.3 ESD Protection
      3. 8.2.3 Application Curves
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Receiving Notification of Documentation Updates
    2. 9.2 Support Resources
    3. 9.3 Trademarks
    4. 9.4 Electrostatic Discharge Caution
    5. 9.5 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

7.3.2 USB Receiver Linear Equalization

The purpose of receiver equalization is to compensate for channel insertion loss and inter-symbol interference in the system before the input of the TUSB1142. The receiver overcomes these losses by attenuating the low frequency components of the signals with respect to the high frequency components. The proper gain setting should be selected to match the channel insertion loss before the input of the TUSB1142 receivers. Two 4-level inputs pins enable up to 16 possible equalization settings when in pin-strap mode. The TUSB1142's USB 3.2 host, hub, and device receivers (SSTX) and USB 3.2 USB connector receivers (CRX1/2) each have their own two 4-level inputs. The TUSB1142 also provides the flexibility of adjusting settings through I2C registers.

The TUSB1142's USB host, hub, and device facing port receiver (SSTX) only support Fixed EQ (FEQ). The TUSB1142 implements three different equalizer features for the USB connector facing port receivers (CRX1 and CRX2): Fixed EQ (FEQ), Fast Adaptive EQ (Fast AEQ), and Full Adaptive EQ (Full AEQ). In Fixed EQ operation, a single setting is used for all possible devices (with and without cable) inserted into the USB receptacle. The Fast AEQ feature will distinguish between a short channel and a long channel. A short channel represents a low loss use case of a USB 3.2 device plugged directly into USB receptacle without a cable. A long channel represents the high loss use case of the USB 3.2 device plugged into the receptacle through a USB cable. In Fast AEQ mode, TUSB1142 will select between two pre-determined settings based on whether or not channel is short or long. When TUSB1142 is configured for Full AEQ, the TUSB1142 will automatically determine what it believes is the best equalization setting each time a USB device is inserted into the USB receptacle. In Full AEQ mode, the TUSB1142 will attempt to determine the best settings regardless if the channel is short, long, or somewhere in between.

Note: Adaptive EQ is only supported on CRX1 and CRX2. Adaptive EQ must only be used when CRX1 and CRX2 is connected to a USB receptacle. If CRX1 and CRX2 is connected directly (not through a USB receptacle) to a USB Host, USB Hub or USB Device, then adaptive EQ must be disabled. AEQ should never be enabled in a active cable application. If daisy chaining multiple TUSB1142, AEQ should only be enabled on the TUSB1142 that is near the USB receptacle.