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TRS3232E-Q1: Query Regarding Short-Circuit Protection for TRS3232EQPWRQ1 in ADAS Application

Rajen Mondal
Prodigy 10 points
Part Number: TRS3232E-Q1

Tool/software:

hello TI Team,

In one of our ADAS projects, we are using the TRS3232EQPWRQ1 (Automotive grade) to support R323 communication protocol.

I have a few queries regarding protection in case of a short-circuit scenario:

We are considering a test condition where the RIN1 and DOUT1 pins may be exposed to a 32V short-to-battery situation.

Currently, we have placed 499Ω resistors (0402, 0.1%) in series with both RIN1 and DOUT1.
Could you please confirm:

  1. Are these resistors sufficient to protect the IC under a 32V short-to-battery condition?
  2. What would be the expected behavior of the IC if this short occurs?
    • Will the internal protection of TRS3232EQPWRQ1 handle this?
    • Is there a risk of permanent damage or degradation?
  3. If the resistors are not sufficient, would you recommend adding a series TVS diode at the connector interface?
    • If yes, could you suggest suitable TVS diode specifications?

Your guidance will help us ensure robust protection and compliance with automotive standards.

Above the schematic image for your reference.

  • 0
    TI__Guru 72901 points
    Rajen Mondal said:
    Are these resistors sufficient to protect the IC under a 32V short-to-battery condition?

    This protects against an overcurrent scenario but the abs max voltage for the device is still outside the range we spec. The device will still be damaged.

    Rajen Mondal said:
    What would be the expected behavior of the IC if this short occurs?
    • Will the internal protection of TRS3232EQPWRQ1 handle this?
    • Is there a risk of permanent damage or degradation?

    Permanent damage will likely occur if the short is sustained.

    Rajen Mondal said:
    If the resistors are not sufficient, would you recommend adding a series TVS diode at the connector interface?

    I think you may need to look at some kind of zener diode since those may be able to handle sustained current but for RS232 you will likely need to also have it bi-directional to ensure it doesn't latch during RS232 operation. 

    https://www.ti.com/lit/ug/tiduer9/tiduer9.pdf?ts=1753901434560&ref_url=https%253A%252F%252Fwww.google.com%252F

    I know the app note above is RS485 but I think the approach could be used for RS232 but you would need to choose a SIDAC that turns on before +/-13V. 

    -Bobby

  • 0 in reply to BOBBY
    Prodigy 10 points

    hello Bobby,

    Thank you for your quick response.

    Could you please suggest some part numbers that are automotive-grade and AEC-Q200 qualified?

    We are looking for components that meet this standard for use in our current project.