AN 672: Transceiver Link Design Guidelines for High-Gbps Data Rate Transmission

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ID 683624
Date 1/29/2020
Public
Document Table of Contents
Document Table of Contents x
1. AN 672: Transceiver Link Design Guidelines for High-Gbps Data Rate Transmission
1. AN 672: Transceiver Link Design Guidelines for High-Gbps Data Rate Transmission x
1.1. PCB Material Selection 1.2. Stackup Design 1.3. Channel Design 1.4. Summary 1.5. Document Revision History for the AN 672: Transceiver Link Design Guidelines for High-Gbps Data Rate Transmission
1.1. PCB Material Selection x
1.1.1. Loss Tangent and Dissipation Factor 1.1.2. Dielectric Constant 1.1.3. Fiberglass Weave 1.1.4. Copper Surface Roughness
1.3. Channel Design x
1.3.1. BGA Channel Breakout 1.3.2. Channel Routing Design 1.3.3. Edge Coupling 1.3.4. Broadside Coupling 1.3.5. Transparent Via Design 1.3.6. Blocking Cap Optimization 1.3.7. Connectors Optimization
1.3.2. Channel Routing Design x
1.3.2.1. Trace Width Selection 1.3.2.2. Loose vs. Tight Coupled Traces 1.3.2.3. Crosstalk Control
1.4. Summary x
1.4.1. PCB Material Selection 1.4.2. Stackup Design 1.4.3. Channel Design 1.4.4. References
1. AN 672: Transceiver Link Design Guidelines for High-Gbps Data Rate Transmission

1.4.1. PCB Material Selection

  • Select the material with the lower loss tangent to reduce signal attenuation from dielectric losses.
  • Always choose lower Ɛr with a flat frequency response for best signal performance and to reduce signal dispersion that adds phase jitter.
  • Always choose more densely woven fiberglass style for the core and prepreg material surrounding the high speed signal layers for more uniform Ɛr that minimizes impedance and signal velocity variations.
  • Choose sparsely dense fiberglass styles for power layers and slower general purpose signal layers to reduce PCB cost.
  • Use wider traces and choose rolled copper foils over traditional electrodeposited (ED) copper foils in the PCB construction to mitigate conductor loss.
  • Certain simulation tools may not include loss effects from surface roughness. In these cases, the correction factor (KSR) must be added to get realistic prediction of the actual loss.
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