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TLIN1022-Q1: UV_HYS

Daniel Wang (auto)
Expert 4680 points

Part Number: TLIN1022-Q1

Hi team,

The car OEM specifies that the LIN hysteresis voltage must be at least 100 mV. During the testing, one channel of the TLIN1022A‑Q1 showed a minimum hysteresis voltage of only  80 mV, which cannot meet the requirement.
 
Test details
  • Test method: The controller is powered from 12 V. The supply voltage is decreased in 0.1 V steps until the LIN node stops communicating. The voltage at which communication is lost was measured as 4.77 V.
  • Then the supply voltage is increased in 0.1 V steps. Communication resumes normally at 4.87 V, but the actual measured recovery voltage is 4.85 V.
  • Hysteresis voltage = 4.85 V − 4.77 V = 0.08 V (80 mV), which is below the 100 mV minimum requirement.
Observation
The same TLIN1022A‑Q1 device, on a different channel, behaves correctly:
  • Communication loss voltage = 4.68 V
  • Communication recovery voltage = 4.83 V
  • Hysteresis voltage = 4.83 V − 4.68 V = 0.15 V (150 mV), satisfying the ≥ 100 mV requirement.
Requested assistance
Do you have a data that what the minimum value of UVHYS? And how to solve this issue?
BR,
Daniel
  • 0
    TI__Guru 70707 points

    Hi Daniel,

    The lowest I see from our validation data is for 0.08 V.

    However, I also suspect the reported 80 mV value is most likely from a system-level communication-loss / recovery test and may not directly reflect the internal UVLO hysteresis of the transceiver and would recommend measuring VSUP directly at the IC pin while monitoring TXD, RXD, and LIN during a slow supply-voltage ramp to help determine whether the communication loss is caused by the IC's UVLO or by another component in the system. 

    Furthermore, the customer’s measured stop / recover voltages (~4.7–4.9 V) seem to be significantly above the data sheet 's UVLO threshold range for UVSUP ≈ 2.9–3.85 V, which could be another indication that the measured communication hysteresis may not be the actual internal UVLO hysteresis. Hence, one of the below should help clarify, thanks

    1. Measure VSUP directly at the TLIN pin
    2. Double confirm the MCU is still fully operational when communication is lost
    3. Confirm the same LIN commander and bus load used on both channels
    4. Monitor RXD, TXD, and VSUP simultaneously
    5. If feasible, perform a continuous voltage sweep rather than 100 mV steps, thanks.

    Best Regards,

    Michael.