SLLA682 July   2025 TDP142

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2Device Configuration
  6. 3Equalization Selection
  7. 4Equalization Selection Example
  8. 5AUXP/N and SNOOPENZ Configuration
  9. 6Layout Guidelines
    1. 6.1 GND Stitching
    2. 6.2 AC-Coupling Capacitors
    3. 6.3 Layout Example
  10. 7Summary
  11. 8References

6.2 AC-Coupling Capacitors

When placing AC-Coupling capacitors, the recommended component size is 0201. The maximum component size used needs to be 0402. During layout, the AC-Coupling capacitors needs to be placed close to the transmitter pins of the device with symmetrical placement to make sure optimum signal quality and to minimize reflections. Place AC-Coupling capacitors as close to the device as possible or on the transmitter side. Figure 6-4 for AC-Coupling capacitor layout symmetry.

AC-Coupling Capacitor Layout Symmetry ExampleFigure 6-4 AC-Coupling Capacitor Layout Symmetry Example
Note: Adding test points to the high-speed traces can cause impedance discontinuity which negatively impacts signal performance. If test points are used, the test points need to be placed in series and symmetrically. The test points must not be placed in a manner that causes a stub on the differential pair.