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TLIN1029-Q1: What is slope control?

Masatoshi Oguri
Expert 4780 points

Part Number: TLIN1029-Q1

Hello,

My customer observes varying rise/fall time on LIN bus. I guess it is because of the difference between master and slave termination. But the slope control is suspicious too.

Thanks.

Regards,

Oguri (TIJ autotmotive FAE)

  • 0
    TI__Guru 53535 points

    Hi Masatoshi-san,

    A typical LIN bus has multiple slave nodes possibly with different driver properties and pull-down strengths and slope control methodologies. Buses may also have several stubs or sub-optimal termination that can introduce signal reflections which may influence the perceived slope at a given measuring point. This will also vary depending on the overall pull-up strength provided by every node as well as the total capacitance of the bus. In a practical system setup you may expect many different rise/fall times when measuring a single point on a LIN bus. If there is a concern, you may want to isolate communication between the master and a single slave and see if there is variation within this case, then move to the next slave.

    I would recommend checking with section 6.8 Timing Requirements on TLIN1029-Q1 datasheet to make sure these variations are acceptable for the device and the system. 

    Let me know if you have any more questions.

    Regards,

    Eric

  • 0 in reply to Eric Schott1
    TI__Expert 4780 points

    Hi Eric,

    Thank you very much for the comment. It solved my other questions.

    But my question was "slope control". The word appears in every LIN datasheet, but I cannot find any information about it. Could you make a brief explanation about it?

    Regards,

    Oguri (TIJ automotive FAE) 

  • 0 in reply to Masatoshi Oguri
    TI__Guru 53535 points

    Hi Oguri,

    My understanding is that the "slope control" circuitry limits the slew rate in LIN and other transceiver typologies to limit Electromagnetic Interference (EMI) emissions. Because LIN networks can vary widely based on the number of nodes and harnessing scheme, this circuitry helps keep the slew rate high enough for reliable data transmission while limiting its maximum to reduce EMI.

    Regards,

    Eric