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SN65HVD11-HT: Mismatch impedance between A/B generating CRC at R

Part Number: SN65HVD11-HT

Dear expert,

We recently experienced a failure involving SN65HVD11-HT for a 200C application where at temperatures above 150C the impedance on A starts to decrease faster than B. At 200C, the impedance measured at A is approximately 850ohms (not powered) as opposed to ~2kohm on B or a working sample. The failure mode is recoverable at lower temperatures (impedance at A is restored). Above 150C the waveform generated at R is sometimes different than the message sent to A/B, resulting in CRC error. At 200C every message has some sort of mismatch. Circuit has 50ohm inline resistors on A/B to limit the current although no external ESD/TVS diodes are installed. Given that this is the only failure we have seen, we are theorizing that it could be the result of an ESD event. Would the failure mode described here be inline with a potential ESD event induced failure?

Your help is greatly appreciated.


  • Annie,

    As the impedance of the A pin decreases, did you see the bus signal become abnormal? I assume the device works in the receiver mode. Have you captured any bus waveform? Do you have any termination resistor installed on the bus?

    Another question is: were the failure devices exposed to any potential ESD event? Do the fresh parts show this behavior? If you want to know the detail about the damage, you can submit the failure analysis through your vendor.