GTS Transceiver PHY User Guide: Agilex™ 5 FPGAs and SoCs

ID 817660
Date 10/17/2025
Public
Document Table of Contents

3.3.11.1. User Guidelines for Setting the TX Equalizer in Loopback Mode

You can use the following recommended settings for the GTS TX PMA equalizer if you are running the Agilex™ 5 GTS transceiver in a loopback mode. Depending on your loopback module, whether it is a cable, optical module or loopback card, follow the recommended TX PMA equalizer setting and the estimated loss value in the table to establish the baseline setting.
  1. Determine loopback path characteristics: First identify the reach mode and insertion loss information of the TX to RX loopback path. You should include all components such as connectors, loopback modules, cables, and PCB traces in your transmission link when you are assessing the total insertion loss value.
  2. Refer to the recommended settings: Refer to the provided table and identify the recommended TX equalizer settings that correspond to your total identified insertion loss value.
  3. Apply the optimum settings: Configure the GTS TX PMA equalizer with the recommended settings for best loopback performance in the Agilex™ 5 GTS transceiver.
Note: You can also use the Transceiver Toolkit to find other TX equalizer settings for your high-speed link, The table below serves as the baseline setting with the estimated insertion loss value and data rate on the link you are testing with the GTS TX to RX PMA loopback.
Table 42.  TX Equalizer Recommended Settings
Data Rate Reach Mode Insertion Loss (X) TX Equalizer
Pre Tap 2 Pre Tap 1 Main Tap Post Tap1
Up to 17.16Gbps VSR X ≤ 10dB 0 0 55 0
MR 10dB < X ≤ 20dB 0 5 55 0
LR 20dB < X < 30dB 0 10 55 0
17.16Gbps to 28.1Gbps VSR X ≤ 10dB 0 0 55 0
MR 10dB < X ≤ 20dB 0 7 55 0
LR 20dB < X < 30dB 0 10 55 0