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Question about RS-485 Tranceiver SN65HVD485

g.f.
Guru 15510 points
Other Parts Discussed in Thread: SN65HVD485E

Hi,

I have a question about RS485 Tranceiver SN65HVD485E.

Can I use SN65HVD485E as RS-422 Tranceiver?

In the datasheet of SN65HVD485E, there are no information about RS-422.

I understand as that RS-485 is compatible to RS-422.

So, I guess I can use SN65HVD485E and other RS-485 Tranceiver as RS-422 Tranceiver, is it correct?

best regards,

g.f.

  • 0
    TI__Expert 5400 points
    Yes, the SN65HVD485E will work as an RS-422 driver/receiver.

    In general, RS-485 is electrically compatible with RS-422. However, some RS-485 transceivers may not necessarily be RS-422 compliant. For example, the SN65HVD485E has a maximum output short circuit current of 250mA, where the RS-422 standard specifies a maximum of 150mA. This will not affect proper operation, but it does preclude the SN65HVD485E from being strictly RS-422 compliant.
  • 0
    TI__Expert 3045 points

    Hi g.f,

    Nice to see you!

    Since RS-485 is upgraded from RS-422, it is OK to use a RS-485 receiver to receive RS-422 signal. I've seen a optical module before which can accept RS-422 and RS-485 signal with a signal RS-485 receiver.

    But it doesn't mean RS-485 and RS-422 are compatible. You need to consider the terminations, driving abilities, common mode voltage, max tolerant voltages on the bus carefully. There's a variety of RS-422 devices on the ti.com , I think you can use RS-422 receivers, which will certainly reduce the potential risk and lower the cost. 

    Hope it helps.

    Best regards,

    Vio Liu

  • 0 in reply to Vio Liu
    Guru 15510 points
    Hi Bart and Vio,

    Thank you for the reply and I'm sorry for the delay.
    I understood.

    best regards,
    g.f.