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DS125DF1610 Rx Common Mode Voltage

Yuval Pazi
Prodigy 150 points
Other Parts Discussed in Thread: DS125DF1610

Hi,

In the DS125DF1610 datasheet, the Rx input is required to have common mode voltage of : Vrx/4<Vcm<Vdd-Vrx/4.

Where does this requirement come from? it is said to have an internal AC coupling - why does the common mode play a role? If I have an AC coupled signal for an input, do I need to give it a DC bias?

Also, what is the input capacitance of the Rx ports?

Thanks,

Yuval

  • 0
    TI__Mastermind 19135 points

    Hi Yuval,

    There is no strict requirement for the user to apply an input common mode voltage to operate the DS125DF1610. The datasheet parameter is more intended to bound the common mode voltage magnitude that can be applied by the user while ensuring optimal performance. We've tested the DS125DF1610 with input common mode of 0V up to 2.5V and not observed impact on performance.

    The DS125DF1610 implements an AC coupling circuit, and the input capacitance is in the order of 100nF-200nF. 

    Cordially,

    Rodrigo Natal

    DPS Applications Engineer

  • 0 in reply to Rodrigo Natal
    Prodigy 150 points

    Thank you for clarifying this.

    Best,

    Yuval