SPRAAR7J November   2018  – February 2023 66AK2G12 , AM1806 , AM1808 , AM2431 , AM2432 , AM2434 , AM3351 , AM3352 , AM3354 , AM3356 , AM3357 , AM3358 , AM3358-EP , AM3359 , AM3871 , AM3874 , AM3892 , AM3894 , AM4376 , AM4377 , AM4378 , AM4379 , AM5706 , AM5708 , AM5716 , AM5718 , AM5726 , AM5728 , AM5729 , AM5746 , AM5748 , AM5749 , AM620-Q1 , AM623 , AM625 , AM625-Q1 , AM625SIP , AM62A1-Q1 , AM62A3 , AM62A3-Q1 , AM62A7 , AM62A7-Q1 , AM62P , AM62P-Q1 , AM6411 , AM6412 , AM6421 , AM6422 , AM6441 , AM6442 , AM6526 , AM6528 , AM6546 , AM6548 , BQ24392-Q1 , HD3SS6126 , LP8727 , OMAP-L137 , OMAP5912 , TMS320C6745 , TMS320DM355 , TMS320DM365 , TMS320DM368 , TMS320DM369 , TMS320DM6441 , TMS320DM6443 , TMS320DM6446 , TMS320DM6467 , TMS320DM8127 , TMS320DM8147 , TMS320DM8148 , TMS320DM8165 , TMS320DM8167 , TMS320DM8168 , TMS320VC5506 , TMS320VC5507 , TMS320VC5509A , TS3USB221A-Q1 , TS3USBA225 , TSU5511 , TSU5611 , TSU6111 , TSU6111A , TSU6721 , TSU8111

 

  1.   Abstract
  2.   Trademarks
  3. 1Introduction
    1. 1.1 Scope
    2. 1.2 Critical Signals
  4. 2General High-Speed Signal Routing
    1. 2.1 PCB Fiber Weave Mitigation
    2. 2.2 High-Speed Signal Trace Lengths
    3. 2.3 High-Speed Signal Trace Length Matching
    4. 2.4 High-Speed Signal Reference Planes
  5. 3High-Speed Differential Signal Routing
    1. 3.1  Differential Signal Spacing
    2. 3.2  High-Speed Differential Signal Rules
    3. 3.3  Symmetry in the Differential Pairs
    4. 3.4  Crosstalk Between the Differential Signal Pairs
    5. 3.5  Connectors and Receptacles
    6. 3.6  Via Discontinuity Mitigation
    7. 3.7  Back-Drill Stubs
    8. 3.8  Increase Via Anti-Pad Diameter
    9. 3.9  Equalize Via Count
    10. 3.10 Surface-Mount Device Pad Discontinuity Mitigation
    11. 3.11 Signal Bending
    12. 3.12 Suggested PCB Stackups
    13. 3.13 ESD/EMI Considerations
    14. 3.14 ESD/EMI Layout Rules
  6. 4References
  7.   A Device Layout Parameters
  8.   Revision History

2.3 High-Speed Signal Trace Length Matching

Match the etch lengths of the relevant differential pair traces of each interface. The etch length of the differential pair groups do not need to match (that is, the length of the transmit pair does not need to match the length of the receive pair). When matching the intrapair length of the high-speed signals, add serpentine routing to match the lengths as close to the mismatched ends as possible. For more details, see #SPRAAR76317.

GUID-E4B09483-FAA0-4915-9B60-9B0AE4AF53D9-low.gif Figure 2-5 Length Matching