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SN751178: can SN65C1168ENSR be pin-to-pin compatible replacement for SN751178NSR

Marvin Cantos
Expert 6670 points
Part Number: SN751178
Other Parts Discussed in Thread: SN65C1168E, , SN65C1168

Hi Team, 

Good day. I am posting this inquiry on behalf of the customer.

"We used SN751178NSR before, but we are looking for a newer replacement

Basically, my question is about the pin-to-pin compatible replacement for SN751178NSR, and it's good if it can be SN65C1168ENSR because it has ESD protection as well."

Please help to advise if this is available. Thank you for extending your support.

Kind regards, 

Marvin

  • 0
    Guru 317250 points

    The SN65C1168E is pin compatible. But is has a narrower input voltage range, and no specifications for a RS-485 termination. Whether this matters depends on the application.

  • 0
    TI__Prodigy 440 points

    Hi Marvin,

    It depends on what the part is being used for. The SN65C1168ENSR is not rated for RS-485 or ITU V.10. But if the costumer is using it for RS-422 or ITU V.11, then it should be fine except for that the differential input voltage is only ±7 for the SN65C1168EN, rather than ±12 for the SN751178. Hope this helps!

    If you have any other questions, please feel free to reach out!

    Zach

  • 0 in reply to Zach Schmidt
    TI__Expert 6670 points

    Hi Zach, 

    Thank you for your response. Please see the feedback from our customer.

    "I saw the answers and there was such things that I faced before actually like lower differential input voltage range,
    but if you don't mind, I can explain the circuit a little more :)
    Actually I built an absolute encoder with AS5045 chip (With SSI interface) and I used SN751178NSR to send and receive data from encoder IC to control PCB (within 1.5m distance).
    so also there is one SN751178NSR on the control PCB. Therefore, the differential lines of this two chip connected to each other.

    is there any problem about such things which your specialists mentioned in that topic?" 

    Thank you for extending your support. Your help is much appreciated.

    Kind regards, 

    Marvin

  • 0 in reply to Marvin Cantos
    Guru 317250 points

    It sounds as if this application uses unidirectional signals, i.e., RS-422.

    When the grounds of the two boards are connected together, then it is safe to assume that the voltage offset is less than 7 V.

  • 0 in reply to Marvin Cantos
    TI__Prodigy 440 points

    Hi Marvin,

    From what I've gathered, this system is similar enough to RS-422 that if it's working with SN751178NSR, then it should work with SN65C1168ENSR, as long as you double check the receiver input voltage range. Hope this helps!

    Zach

  • 0 in reply to Zach Schmidt
    TI__Expert 6670 points

    Hi Zach, 

    Thank you for your response. Please see the feedback from our customer.

    "I've checked those technical info which provided by your specialist at the forum, so basically I think the problem is resolved about 70% :) 
    also I decided to check differential signals in the circuit (Drivers output or Receiver input) and share the waveforms with you and the guys in the forum, so please if possible, upload the photos in the topic. as you can see, Max voltage of all signals is about +4.0V and the Min Voltage is also about -4.0V. (Vpp is around 8V), 
    so I think there shouldn't be a problem with SN65C1168. 

    another note is that the circuit working with single 5V supply, I mean the two SN751178 and the Encoder chip, also there is common ground between all of them. 

    Thanks again for helping me :) "

    Thank you for extending your support. Your help is much appreciated.

    Kind regards, 

    Marvin

  • 0 in reply to Marvin Cantos
    Guru 317250 points

    Everything sounds OK; this will work.

  • 0 in reply to Marvin Cantos
    TI__Prodigy 440 points

    Marvin,

    Yup! I can't see the photos if they were uploaded, but from the description, everything sounds. good and well under the limit.
    Please reach out with anything else!

    Zach

  • 0 in reply to Zach Schmidt
    TI__Expert 6670 points

    Hi Zach, Clemens, 

    Thank you for your help. Please see the photos from the customer.

    Kind regards, 

    Marvin

  • 0 in reply to Marvin Cantos
    TI__Prodigy 440 points

    Marvin,

    yup, the voltages on the waveform look good for the swapped parts! Let us know if you have any other questions!

    Zach