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TLIN1021A-Q1: SAE2602 Test

mingyue zhang
Prodigy 10 points
Part Number: TLIN1021A-Q1


Tool/software:

Hello!
When using the TLIN1021ADRBRQ1 chip, we tested the SAE2602-1 standard and had the following requirements:

VECU=8V,The commander-node must transition from waking to not waking in response to the wake- up message wher 4.8 V ≥Recessive LIN bus voltage ≥ 3.29 V.

We use it as a slave mode.

However, according to the manual, only the minimum High level given to LIN is 0.6xVSUP=4.8V. We have measured that it fails at 6.09V, which is within the scope of the manual but does not meet the SAE2602 standard and needs to fail between 3.29V-4.8V.

  • 0
    Prodigy 10 points

    Correction:VECU=8V,The responder-node must transition from waking to not waking in response to the wake- up message wher 4.8 V ≥Recessive LIN bus voltage ≥ 3.29 V.

  • 0
    TI__Genius 9340 points

    Part Number: TLIN1021A-Q1

    Tool/software:

    Hi  Team, 

    We are having some test on TLIN1021ADRBRQ1.

    According to SAE2602, with 8V supply, the no responds voltage of LIN communication should within 3.29-4.8V.

    While in the datasheet, there is only the minimum recessive voltage 0.6xVsup=4.8V. While the test results shows it bus down at 6.09V. Although it is within the datasheet range, but it is not aligned with SAE2602(3.29~4.8V).

    Best,

    Frank

  • 0 in reply to mingyue zhang
    TI__Mastermind 26836 points

    Mingyue,

    I'm having trouble finding the specific test you're referring to in SAE J2602-1/J2602-2. Could you clarify which test/section number you're looking at?

    Best,

    Danny

  • 0 in reply to Danny Bacic
    TI__Mastermind 26836 points

    Mingyue,

    Ok, actually, it looks like I've found the spec you're referring to. Are you looking at 7.4.1.4.1 in SAE J2602-2? This is covered by the TLIN1021A-Q1. The threshold for recessive/HIGH signals is given in the data sheet as VIH, which ranges from 0.47*VSUP to 0.6*VSUP. When VSUP ≈ 8V, the recessive threshold is somewhere between 3.76V and 4.8V, which meets this requirement.

    If you're having trouble with the test, please feel free to pass along some waveforms and we can help diagnose what's going on.

    Best,

    Danny

  • 0 in reply to Danny Bacic
    TI__Mastermind 26836 points

    Mingyue, Frank,

    I have merged your threads as it appears you are asking the same question. If this is a mistake, please let me know.

    Best,

    Danny

  • 0 in reply to Danny Bacic
    Prodigy 10 points

    Hi Danny:

         It's section 7.4.1.4.1 in the SAE2602-2 standard. May I ask what is the difference between the two values in the datasheet?

  • 0 in reply to mingyue zhang
    TI__Mastermind 26836 points

    Mingyue,

    VBUSdom and VBUSrec are requirements of your system. In other words, if you want to guarantee that the device will interpret a signal as dominant, then you need to provide the input below 0.4*VSUP, and if you want to guarantee that the device will interpret a signal as recessive, then you need to provide the input above 0.6*VSUP.

    VIH and VIL are the actual thresholds where the input signal will change. So, if you slowly raised the LIN bus from 0V toward VSUP, the receiver would switch from dominant to recessive at VIH, which may range from 0.47*VSUP to 0.6*VSUP for different devices. Also, if you slowly lowered the LIN bus from VSUP toward 0V, the receiver would switch from recessive to dominant at VIL, which may range from 0.4*VSUP to 0.53*VSUP for different devices.

    For your system, these are basically two different ways of saying the same thing: The receiver will interpret signals above 60% of VSUP as recessive and signals below 40% of VSUP as dominant.

    Best,

    Danny

  • 0 in reply to Danny Bacic
    Prodigy 10 points

    Hi Danny:

          Sorry, I still don't understand the difference between the two values. Can you explain in detail the difference between VBUSrec and VIH?

    Best,

    Mingyue

  • 0 in reply to mingyue zhang
    Prodigy 10 points

    Addendum: During our testing, we found that LIN had a waveform at 6.09V, but the chip no longer responded. If we continue to reduce the power supply 2, LIN will become a straight line and have no waveform at all.I will retest later and display the waveform.

  • 0 in reply to mingyue zhang
    TI__Mastermind 26836 points

    Mingyue,

    To explain more simply, the VBUSdom and VBUSrec are input requirements.

    VIH and VIL describe where the actual thresholds might be located, which could possibly be less than 0.6*VSUP and above 0.4*VSUP.

    Best,

    Danny