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SN65MLVD201: For M-LVDS Failsafe Biasing Application

ArTzy
Mastermind 19440 points
Part Number: SN65MLVD201


Hi Expert,

Using MLVDS - SN65MLVD201D, we have question about this part regarding the Failsafe biasing of MLVDS. We want to ensure that customer are following the information in the data sheet to choose the resistors.


R3 = ~ 5kohm and R1= 8kohm

Please advise if you recommend different values base on the requirement.

Regard,
Archie A.

  • 0
    TI__Intellectual 1150 points

    Hi Archie

    SN65MLVD201 has type-1 and typ-2 options.. SN65MLVD201D is type-1. 

    Type 1 receivers include no provisions for failsafe and have their differential input voltage thresholds near zero volts. Type 2 receivers have their differential input voltage thresholds offset from zero volts to detect the absence of a voltage difference.

    If type-2 fail safe receiver is chosen for fail safe and better noise immunity, please refer to datasheet VID spec table (Table-3) to make sure the voltage drop on R2 in your schematic is in the correct VID region so the part is correctly biased.

    Thanks,

    Yuan

  • 0 in reply to Yuan Rao
    TI__Mastermind 19440 points

    Hello Yuan,

    Thanks for the information

    In this case using SN65MLVD201D base on the data sheet, it would require for failsafe because its type 1. What is the recommended values that works for this application as shown in the image below? for R3 = ~ 5kohm and R1= 8kohm and both (R2 and R4 100 ohm) with VCC 3.3v:

    Please advise. Thank you.

    Regards,
    Archie A.

  • 0 in reply to ArTzy
    TI__Guru 60827 points

    Hi Archie,

    The equivalent resistance of the network R1, R2 and R3 needs to be equal to the characteristic impedance of the cabling. Please help see How much loading can an auto-polarity RS-485 bus support? for further clarification, thanks.

    Best Regards,

    Michael.