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DS320PR810: Clarification on CTLE and Flat Gain Setting Procedure

QIANWEN WANG
Prodigy 110 points
Part Number: DS320PR810


Tool/software:

Hi TI supprot,

I have a question regarding the procedure for setting the CTLE and flat gain levels on the DS320PR810.

In my test case, I intend to configure the CTLE to index 6 with a flat gain of 0 dB.

Here are the steps I followed:

  1. First, I wrote 0x81 = 0x08 and 0x83 = 0x0D according to the CTLE setting matrix.

  2. Then, I manually adjusted the flat gain by writing 0x83 = 0x05 to set it to 0 dB.

As a result, the final register values are 0x81 = 0x08 and 0x83 = 0x05, which differ from the initial values shown in the standard setting matrix.

My questions are:

  • After setting the CTLE index according to the matrix, is it necessary to manually adjust the flat gain separately if a different flat gain is desired?

  • In this specific case, does setting 0x83 = 0x05 instead of 0x0D affect the overall CTLE performance, or are the results functionally equivalent?

I would appreciate your clarification on this.

Thank you very much for your support.

  • 0
    TI__Mastermind 20711 points

    Hello Qianwen,

    Thank you for reaching out with your questions on the DS320PR810. Please allow me to address your inquiries below.

    • The redriver's equalization settings are set manually through the settings you have mentioned above - CTLE Index and Flat Gain. It is necessary to adjust the Flat Gain manually if a different Flat Gain setting is desired.
    • Setting 0x83 = 0x05 instead of 0x0D will affect overall CTLE performance and would select a different CTLE Index. Writing 0x0D (0b00001101) to register 0x83 will set both the flat_gain[2:0] and eq_profile[3:0] fields of register 0x83 to the appropriate values for CTLE Index 6, Flat Gain 0dB. Please refer to Table 2-10 for the register description of Channel Register offset 0x3 and Table 3-1 for further details on the CTLE Equalization Setting details.

    Best,
    David