SLLSEJ1A March   2014  – March 2014 TUSB551

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Simplified Schematic
  5. 5 Revision History
  6. 6 Terminal Configuration and Functions
  7. 7 Specifications
    1. 7.1  Absolute Maximum Ratings
    2. 7.2  Handling Ratings
    3. 7.3  Recommended Operating Conditions
    4. 7.4  Thermal Information
    5. 7.5  Power Supply Electrical Characteristics
    6. 7.6  DC Electrical Characteristics
    7. 7.7  AC Electrical Characteristics
    8. 7.8  Timing Requirements/Timing Diagrams
    9. 7.9  Switching Characteristics
    10. 7.10 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Receiver Equalization
      2. 8.3.2 De-Emphasis Control and Output Swing
      3. 8.3.3 Automatic LFPS Detection
    4. 8.4 Device Functional Modes
      1. 8.4.1 Receiver Equalization Settings
      2. 8.4.2 De-Emphasis Control Settings
      3. 8.4.3 Output Swing Control Settings
  9. 9 Applications and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Transmit and Receive Channels
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
        3. 9.2.1.3 Application Performance Plot
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Trademarks
    2. 12.2 Electrostatic Discharge Caution
    3. 12.3 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

8 Detailed Description

8.1 Overview

When 5Gbps SuperSpeed USB signals travel across a PCB or cable, signal integrity degrades due to loss and inter-symbol interference. The TUSB551 recovers incoming data by applying equalization that compensates for channel loss, and drives out signals with a high differential voltage. This extends the possible channel length, and enables systems to pass USB 3.0 compliance.

The TUSB551 advanced state machine makes it transparent to hosts and devices. After power up, the TUSB551 periodically performs receiver detection on the TX pair. If it detects a SuperSpeed USB receiver, the RX termination is enabled, and the TUSB551 is ready to re-drive.

The device’s ultra low-power architecture operates at a 1.8V power supply and achieves enhanced performance. The receiver equalizer has three gain settings that are controlled by terminal EQ: 3 dB, 6 dB, and 9 dB. The equalization should be set based on amount of insertion loss in the channel before the TUSB551. Likewise, the output driver supports configuration of De-Emphasis and Output Swing (terminals DE and OS). The automatic LFPS De-Emphasis control further enables the system to be USB3.0 compliant.

The TUSB551 operates over the industrial temperature range of -40ºC to 85ºC in the 1.6mm x 1.6mm X2QFN package.

8.2 Functional Block Diagram

fbd_llsej1.gif

8.3 Feature Description

8.3.1 Receiver 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 TUSB551. 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 TUSB551.

8.3.2 De-Emphasis Control and Output Swing

The differential driver output provides selectable de-emphasis and output swing control in order to achieve USB3.0 compliance. The TUSB551 offers a unique way to adjust output de-emphasis and transmitter swing based on the OS and DE terminals. The level of de-emphasis required in the system depends on the channel length after the output of the re-driver.

trans_llsej1.gifFigure 10. Transmitter Differential Voltage, OS=Floating

8.3.3 Automatic LFPS Detection

The TUSB551 features an intelligent low frequency periodic signaling (LFPS) controller. The controller senses the low frequency signals and automatically disables the driver de-emphasis, for full USB3.0 compliance.

8.4 Device Functional Modes

8.4.1 Receiver Equalization Settings

TERMINAL DESCRIPTION LOGIC STATE GAIN
EQ Equalization amount Low 3 dB
Floating (NC) 6 dB
High 9 dB

8.4.2 De-Emphasis Control Settings

TERMINAL INTERNAL TIE LOGIC STATE DE-EMPHASIS RATIO
FOR OS = LOW FOR OS = FLOATING
DE De-emphasis amount Low 0 dB 0 dB
Floating (NC) -2 dB -3.5 dB
High -4 dB -6 dB

8.4.3 Output Swing Control Settings

TERMINAL INTERNAL TIE LOGIC STATE OUTPUT DIFFERENTIAL VOLTAGE
OS Output swing amplitude,
DE = Low		 Low 1050 mVpp
Floating (NC) 1200 mVpp