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LVDS32 instead of comparator

Orikasa
Expert 6340 points

Support team,

As I attached the drawing, our customer plans to use LVDS32 instead of high speed comparator. According to the customer, input signal will be 1.5V to 5V ( depends on the length of the cable) and will adjust the Vcm with a variable resistor. Could you check the attached file and let me know if you notice something wrong.

Thanks

Ori

lvds-comp.ppt
  • 0
    TI__Intellectual 1500 points
    Hello Ori-san,

    The differential voltage should be greater than 100mV or lesser than -100mV for a determinate output of High or Low respectively.  In the circuit, when the resulting differential input signal swing is less than 200mV, it would lead to indeterminate output.

    Attached (rough) figure shows the input voltage requirement.  In the figure, even though Vib is controllable by the variable resistor, but the differential voltage = Via - Vib should have at least 100mV swing in both directions.

    Thus, V+ should be atleast 0.20Vpp, a solution of which could be to adjust the value of R1 and R2 in order to have greater voltage swing.

    Thanks.
    Ankur Verma
    High Speed Interface Applications