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SN75C3243: Question about ESD specification

Guru 11745 points

Part Number: SN75C3243

Customer is testing SN75C3243 for ESD rating, a few device were abnormal operation.

Please let me know about three points below.

①Is there ESD specification for the other than 15kV HBM? (DIN / DOUT rating, etc)

②Are DIN and DOUT should connect TVS diode?

③After ESD test, a few device are floating output, is this likely occur?



・ESD test condition: 11kV / 0.5sec (×several times)

・Abnormal operation: After ESD test, DOUT is drop 0.8V~1.0V (normal is 5Vout)

・After ESD test, all DIN were no problem.

Best regards,


  • Hello Satoshi-san,

    This part is only specified for HBM ESD (up to 15 kV). TVS diodes could be used externally if you need to subject the part to higher-stress transients. This would more likely be on the RS-232 signals (which would interface externally) than the lower-voltage logic signals (which typically remain on the application PCB).

    Typically ESD failures result in short circuits or increased leakage rather than floating outputs, but it is possible for high-current stresses to cause units to have open-circuit failures (floating outputs).

    If you want to get a better understanding of the nature of the damage to these units you could request a failure analysis be performed by TI. Let me know if you need any explanation on how to go about this process.