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DS80PCI800 combining 4-level inputs

Alex Kolesnyk
Prodigy 150 points

Other Parts Discussed in Thread: DS80PCI800

Hello,

can somebody tell me how many 4-level inputs can be combined together?

There is the system with eight DS80PCI800 chips: 32 lanes total  for redriving.

EQ and De-emphasis settings are equal for all channels, so all EQ control pins are connected together and all DEM control pins are connected together also.

I have scaled down values of the pullup and pulldown resistors (1/16): 1k -> 62R, 20k -> 1.24k

Can i use eight DS80PCI800 with above resistors?

Tks

Alex

  • 0
    TI__Mastermind 43795 points
    Hi Alex,
    If several 4-level inputs require the same setting, it is possible to combine two or
    more 1-kΩ resistors into a single lower value resistor. As an example; combining two inputs with a single 500-Ω
    resistor is a good way to save board space. For the 20 kΩ to GND, this should also scale to 10 kΩ.
    For 16 4-level inputs tied together your resistor values are correct. 1K -> 62.5 Ohms and 20K -> 1.25K
    Regards,Lee
  • 0 in reply to Lee Sledjeski
    Prodigy 150 points

    Hi Lee,

    I had doubts regarding to so more inputs connected together.

    thank you for your confirmation

    Regards,

    Alex