E-Tile Transceiver PHY User Guide

ID 683723
Date 9/30/2022
Public
Document Table of Contents

3.1.3.3. PMA Tuning Guidelines

  1. Run the STF across the desired temperature sweep. There is no need to run the DTF if the STF provides a good BER across the temperature sweep.
  2. If optimal performance is not achieved, then sweep GS1 and GS2 first. Then, enter the best settings, sweep the RF_B0 and RF_B1 parameters, and run initial adaptation at static temperatures (low and high). After understanding the trend of these parameters at static temperature, record the optimum value of these parameters which results in the optimum performance across the desired temperature sweep range.
  3. Set the optimum parameters you recorded and initiate initial adaptation. Sweep the temperature in steps of 1°C per minute and run continuous adaptation to track the temperature variations in PMA.
    This bring up flow becomes the DTF if the link performance is optimum across the temperature sweep.
  4. If optimal performance is not achieved, then add a sweep of the RF_B1/GS1/GS2 parameters and initiate continuous adaptation to the bring up flow used in Step 3. When you have achieved optimal link performance, you have completed the DTF bring up.
    Figure 55. PMA Tuning Generic Flow

    You can use the PMA parameter configurations in the table below for the specified data rate and channel loss. Refer to PMA Parameter Description and Range for details about the parameters listed below.

    Table 45.  PMA Parameter Tuning for Extending Dynamic RangeThese are the tuned PMA parameter settings that result in optimal link performance across a temperature sweep for each test configuration. An integer value means that the parameter is fixed unless stated otherwise, and Firmware Default means that the parameter starts with the Firmware Default value and that the parameter may adapt if it can be adapted by the adaptation tuning engine. (Refer to PMA Parameter Description and Range for the Firmware Default values and whether or not the parameter can be adapted by the adaptation tuning engine.) Use the following PMA configurations as a starting point across process voltage and temperature. Further tuning is required if the BER does not meet the required protocol specifications.
    Parameter PAM4 NRZ
    56 Gbps 28 Gbps 10 Gbps
    LR VSR LR VSR 25 dB/15 dB/10 dB
    PMA Tuning Configuration Before Running Initial Adaptation
    RF_A 130 130 130 160 160
    GS1 1 0 2 0 2
    GS2 1 0 2 0 1
    RF_B0 218 3 1 Firmware Default 19 1
    RF_B1 8 3 1 5
    CTLE LF maximum 2 15 3 15 2
    CTLE LF minimum 0 0 0 0 20 0
    CTLE HF maximum 15 15 15 1520 15
    CTLE HF minimum 0 0 0 0 0
    RF_P1_MAX 15 15 6 15 15
    RF_P2 Firmware Default19 Firmware Default19 0 Firmware Default19 0
    RF_B0T 40 10 10 20 20
    PMA Tuning Configuration Before Running Continuous Adaptation
    RF_B1 Same as initial adaptation Same as initial adaptation 8 Same as initial adaptation Same as initial adaptation
18 This parameter is set to adaptive.
19 Firmware Default means that the parameter starts with the Firmware Default value and that the parameter may adapt if it can be adapted by the adaptation tuning engine. (Refer to PMA Parameter Description and Range for the Firmware Default values and whether or not the parameter can be adapted by the adaptation tuning engine.)
20 When you use low effort initial adaptation and have 25G/28G optical modules, better results can be achieved using CTLE LF minimum = 7 and CTLE HF maximum = 7.

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