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TRS3223-Q1: How to protect DOUT and RIN pin from shorting to supply

Wei-Hao Chen (TW-FAE)
Expert 3260 points
Part Number: TRS3223-Q1

Hi Experts,

My customer would like to use TRS3223-Q1 into a automotive system, but they need to take account for the risk of signals shorting to vehicle PbA battery.

Can you please teach us if there is any circuit to protect DOUT and RIN pins shorting to the battery? The maximum battery voltage can go upto 18v, the RIN should be fine but the DOUT can only handle up to 13.2V and might have the risk to cause damage on TRS3223-Q1.

We tried to add schottky diode in series with DOUT pin to block the reserve battery voltage if the terminal connector is shorted to battery, but this will affect the communication under normal condition.

We need a solution to protect TRS3223-Q1 from failure under the short condition, while not affecting the communication under normal working condition.

Any suggestion would be greatly appreciated.

Thank you.

Best Regards,

Wei-Hao

  • 0
    TI__Mastermind 25705 points

    Wei-Hao,

    Do you know when the short could happen? If the driver is on, to protect the driver that is short to 18V DC, I think one way is adding some series resistor. The driver is integrated with the short circuit current protection (30mA typical). Therefore 200Ohm may generate enough voltage drop to bring the voltage at the pin less than the abs max. If the driver is off, you may have to rely on external diode to clamp the bus voltage less than 13V. The diode should be back to back bipolar type.  

    Regards,

    Hao