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DS90LV001: both input 100ohm termination and output terminate are needed for DS90LV001, is it right? Comparing with DS10BR150

Ken Zhang
Expert 3140 points
Part Number: DS90LV001
Other Parts Discussed in Thread: DS10BR150

hi, 

      In DS10BR150，  both 100Ω Input termination and 100 Output Termination are integrated。 but for DS90LV001, there is no any in-chip termination.

    Is it means that both external 100 input termination and 100 output termination must be added in design for 500MHZ LVDS signal?

  • 0
    TI__Guru**** 168361 points

    Hi,

    A termination resistor is required only on the input. It should match the characteristic impedance of the transmission line (90Ω to 110Ω).

    Thanks

    David

  • 0 in reply to David (ASIC) Liu
    TI__Expert 3140 points

    David;

    why is a 100 output termination integrated in DS10BR150, but 100 ohm output termination is not needed in DS90LV001?

  • 0 in reply to Ken Zhang
    TI__Guru**** 168361 points

    Hi,

    The output resistor on this part helps to match the output impedance with the transmission line impedance.  This is necessary for good transmission characteristics.

    Thanks

    David

  • 0 in reply to David (ASIC) Liu
    TI__Expert 3140 points

    I  am confused with below message. does below comments mean that adding 100ohm output termination on DS90LV001 is preferred?

         

    The output resistor on this part helps to match the output impedance with the transmission line impedance.  This is necessary for good transmission characteristics.

  • 0 in reply to Ken Zhang
    TI__Guru**** 168361 points

    Hi,

    Internal 100-ohm resistor provides back termination. This back termination, with the100-ohm termination at the receiver, and the controlled trace impedance, provide optimum signal conditioning from signal integrity point of view. Otherwise there could be reflection - due to impedance mis-match.

    On the other hand, a normal buffer, such as the DS90LV001 would operate at a much lower data rate and thus meeting tight impedance controlled environment is not a concern as much, so you do not need 100ohm termination at its output.

    Thanks

    David