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MAX3491AE ESD protection, TVS diodes?

Thread Summary

The user inquired about the presence and characteristics of TVS diodes in the MAX3491AE. The final answer confirmed that the MAX3491AE does not have internal TVS diodes but instead uses a bidirectional SCR for protection, which provides a low impedance when triggered. The design engineer could not provide further details on the protection characteristics due to lack of access to the internal schematic.
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Category: Hardware
Product Number: MAX3491AE

Does the MAX3491AE have TVS diodes internal to the die and are they unidirectional.  Are they connected on the transmitter pins and what is their power rating and break down voltage if so.  We had a case were the transceiver was isolated and improper grounding caused a large potential difference between chassis and ground causing a possible TVS diode to conduct, burn out and short.  If they were TVS diodes were they designed to fail high Z, open, or short?  I know it is hard to predict their failure state, but curious if any design work has been done to get a direction as to their expected failure state.

  • ADI North America will be on winter shutdown starting December 25, 2023; perhaps another community member can assist you until our return on January 8, 2024.
  • Hi PatrickSpace,

    The MAX3491AE does not have an internal TVS diode but a bidirectional SCR (which behaves like a TRIAC). The SCR will snap back once the trigger point is reached, providing a low impedance. I reached out to the design engineer for more information, but unfortunately he can no longer access the internal schematic, so I am unable to provide more information on the protection characteristics. I hope this helps with your troubleshooting.