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SN65LVDS1: Compatibility with lvds2.5V (2.5V LVDS +/2.5V LVDS - )?

Rice,Lee
Intellectual 350 points
Part Number: SN65LVDS1
Other Parts Discussed in Thread: SN65LVDT2,

Tool/software:

I'm trying to configure an LVDS2.5V interface using SN65LVDS1 and SN65LVDT2.

Would it be okay to use SN65LVDS1 (power supply +2.5V) and SN65LVDT2 (power supply +3.3V) to make it compatible with the LVDS2.5V interface circuit?

  • 0
    TI__Genius 9816 points

    Hi Lee,

    Yes that will work. LVDT2 can accept any input voltage that is between 0 and Vcc-0.8 wrt GND. The max output voltage for LVDS1 is 454mV with a max common mode of 1.375V. That gives us a max single ended voltage of 1.375 + (0.454 / 2) = 1.602V, which is within spec. 

    Regards,

    Matt  

  • 0 in reply to Matt Smith
    Intellectual 350 points

    High Matt,

    Why is it possible? What is the basis for this? Is there a detailed reference?

    Thanks.

  • +1 in reply to Rice,Lee
    TI__Genius 9816 points

    Hi Lee, 

    The basis for this are the highlighted specs below:

    If the Vcc of your receiver is 2.5V, that means any input pin on the device can withstand 1.7V since 2.5-0.8 = 1.7 (referring to the input pin spec). You can calculate what the max single ended voltage the driver will output with the following equation: 

    max single ended voltage = V_OC + (V_OD / 2)

    This is the equation i used in my previous response to come to the 1.602V answer. Since 1.602 is less than 1.7, the device is being used within spec. Therefore this is a valid use case. 

    Regards,

    Matt