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Transient Protection for AM26C31 Driver

Other Parts Discussed in Thread: AM26C31

Hi, I am an electrical design engineer and I am doing a lightning analysis for an engine control system that I am designing. I am using one TI's differential line drivers (AM26C31) in my application. I protect the outputs of the driver with diodes clamping to ground and also to a zener diode, escentially acting as a transzorb. The concern I have is that this method clamps the output ines to either -2V or 6.5V, but the device is rated to have a maximum output voltage range of -0.5V to 7V. It is my understanding that this maximum output voltage range is a DC value. Is there a maximum transient voltage range? The lines will be clamped at this voltage for a duration of 200 microseconds, max. Is there any guarantee that the part will survive this clamping range for the duration of the fast transient? Any information you can provide will be greatly appreciated.

Thank you.

  • while the use of steering diodes and transzorbs you describe is commonly used for short tramsiemts such as ESD or EFT, for longer transients it is recommeded to add some 5 ohms to 10 ohms surge-rated MELF resistors into the signal lines (between the driver outputs and the steering diodes.

    these resistors will limit the current into the device during clamping action.

    best regards,

    Thomas