SLLA642 July   2024 TUSB564-Q1

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2USB Type-C With DisplayPort Alt-Mode
    1. 2.1 USB Type-C Basics
    2. 2.2 Adding USB3
    3. 2.3 Adding DisplayPort Alt-mode
  6. 3USB 4-Meter System
  7. 4USB 9-Meter System
  8. 5DisplayPort 4.6-Meter System
    1. 5.1 5.4Gbps
    2. 5.2 8.1Gbps
  9. 6DisplayPort 9.2-Meter System
  10. 7Summary
  11. 8References

6 DisplayPort 9.2-Meter System

To simulate a long cable DisplayPort system, two 4.6-meter DisplayPort cables are used in the signal path. One cable is placed before the TUSB564-Q1, and the second cable is placed after the TUSB564-Q1. The bench board adds additional loss with it's short pre and post-channel FR4 trace. A DisplayPort source is connected upstream, and measurements are taken at the end of the downstream DisplayPort cable.

DisplayPort 9.2-Meter System Block Diagram Figure 6-1 DisplayPort 9.2-Meter System Block Diagram

For this test, a 5.4Gbps DisplayPort signal is used. The equalization on the TUSB564-Q1 is set to #9. This adds 11.0dB of gain on the DisplayPort lanes routing through the device. Following are the results of a 5.4Gbps DisplayPort compliance test taken at the downstream end of this system.

DisplayPort 9.2-Meter System Test Results Lane 0 Figure 6-2 DisplayPort 9.2-Meter System Test Results Lane 0
DisplayPort 9.2-Meter System Test Results Lane 1 Figure 6-3 DisplayPort 9.2-Meter System Test Results Lane 1
DisplayPort 9.2-Meter System Test Results Lane 2 Figure 6-4 DisplayPort 9.2-Meter System Test Results Lane 2
DisplayPort 9.2-Meter System Test Results Lane 3 Figure 6-5 DisplayPort 9.2-Meter System Test Results Lane 3

The compliance test is able to pass in this configuration with no issues. The eye diagram shows a defined eye opening and transition area. At 5.4Gbps, the TUSB564-Q1 has enough compensation to drive a DisplayPort signal through 9.2 meters of cable with margin to spare.