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TLK2711A in ac-coupled dc-bias resistors

does TLK2711A driver connected in ac-coupled need a dc-bias resistors to GND on TXP and TXN?

it is needed for the source dc current.

thanks in advance

  • Hi Haim,

    In datasheet of the TLK2711A (Figure 12), you can check that for AC-coupled mode, the device provides its own internal bias point. Hence, you will not need an external network to set the common mode.

    Regards!

    Luis Omar Morán Serna
    High Speed Interface Group
    SWAT Team
  • i am not familiar with the VML driver type of the TLK2711A, but in LVPECL driver in ac-coupled, resistors to GND are required since output transistors should not be completely turned off. do you have a different recomendation?

    Thanks in advance.

  • Hi Haim,

    VML drivers are voltage-level compatible with LVPECL.
    Like CML, these drivers are implemented in CMOS, but have the advantage that they do not require external pullup resistors, because of the use of internal MOS and PMOS transistors to help drive the falling and rising edges. While VML is not yet as widely implemented as the other drivers, it still remains voltage-compatible with LVPECL signaling levels and has been used in many of TI’s production devices. Current Texas Instruments serial gigabit solution devices that have an integrated VML driver are the TLK2711, TLK3101, TLK1201, TLK2201, TLK2208, TLK3104SA, TLK3114SA, TLK3104SC, TLK4010(1), SLK2501, SLK2511, SLK2701, SLK2721, and the SLK2504.

    Below you can see the input/ouput stage (typical structure):

    Regards!

    Luis Omar Morán Serna

    High Speed Interface Group

    SWAT Team