PCB High-Speed Signal Design Guidelines: Agilex™ 5 FPGAs and SoCs

ID 821801
Date 11/18/2024
Public
Document Table of Contents

3.6.1. GTS Transceiver Channel Recommendations

  • PCB Route Length: max 1.2 inches on SOM and 2.2 inches on the carrier board. Evaluate max routing length based on specific stack-up and standards.
  • Pair-pair spacing: 5H (TX-TX, RX-RX), “H” is the distance from the signal layer to the closest reference layer.
  • Pair-pair spacing: 9H (TX-RX), “H” is the distance from the signal layer to the closest reference layer.
  • Insertion loss should meet the requirement of IEEE spec.
  • N/P routing should be as symmetrical as possible.
  • HSSI traces must be fully enveloped by GND plane.

Informative

  • Target Differential Impedance: 90 Ω on SOM and carrier board (95 Ω is also possible depends on stack-up design).
  • Differential RL lower than -15 dB from 0 to Nyquist frequency (depends on specific data rate).