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Part suggestion for SPI signal buffer

Other Parts Discussed in Thread: SN74LVC125A, SN74AUC125, TIDA-060017

Hi,

Greetings!

I have this below query!

We are searching an SPI buffer for our application where spi signals go out of the board to another board with cable lenght <1m. Could you please suggest any active components available? 

  • Mahesh,

    An engineer has been notified of this post and will respond by the end of business CST on 02/29/2022.

    Regards,

    Eric Hackett 

  • Hi Mahesh,

    I don't believe we have any SPI buffers. However, I have seen customers in the past use RS-485 to turn the SPI signal into a differential signal and send it across long distances that way. We have an app note written on that here. If this is something that you would be interested in let me know and I can offer some recommendations for devices.

    If you would like to keep it single ended you can try RS-232. However, a differential signal will allow you to send the signal over a longer distance and will keep the signal more robust to noise.

    Best,

    Chris

  • SPI uses plain logic signals, so you could use a logic buffer. The strongest families are LVC (e.g., SN74LVC125A) at 3.3 V and AUC (e.g., SN74AUC125) at lower voltages. However, there is no guarantee that this works with a long cable (this depends on the cable's capacitance, its shielding, and on the environment).

    For differential signalling, you can use RS-485 or LVDS; SPI is typically implemented with the latter. For an example, see TIDA-060017: