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using MC3486 IC

Sumitra Bhosale
Prodigy 10 points
Other Parts Discussed in Thread: MC3486

Hi,

I am using encoder which is having rs422 differential output I need to interface this signal with controller. For that I am using MC3486 line receiver IC. I have given A,A- signals to input of MC3486 IC and ouput of this to controller interrupt. same way B,B- to other inputs and output of it to controller.

Do I need any resistors or other component to connect at IC input/output?? 

  • 0
    TI__Guru 62920 points
    Hi Sumitra,

    RS-422 interfaces are typically terminated at the furthest receiving node using a resistance between A and A- that is matched to the impedance of the cabling (most often 100 Ohms or 120 Ohms). This helps improve signal integrity by reducing the amplitude of reflections that could occur at the end of the line. Some people may choose to also implement a weak pull-up resistance on the A line and a weak pull-down resistance on the A- line so that the receiver detects a "high" signal when the driver on the other side is inactive, disconnected, etc.

    Other than that, it is good practice to use a decoupling capacitor (100 nF) on the VCC pin of the device, and you may want to use pull-up or pull-down resistors on the enable inputs (so that they are defined even if they are not driven by your controller) and on the single-ended outputs so that they have a defined level when disabled.

    I hope this helps, and please let us know if you encounter any issues.

    Max