The logic state when inputs OPEN between ADM3485 and ADM3485E

   Dear Sir

   Nice to meet you!

   We found the  different logic state when inputs are unconnected  between ADM3485 and ADM3485E.

   ADM3485:      When inputs open.   A=0.1V   B=0.1V  RO=0V        (/RE=0V and DE=0V)

   ADM3485E:   When inputs open.   A=1.8V   B=1.8V  RO=3.3V     (/RE=0V and DE=0V)

   However in the Data sheet of both ADM3485 and ADM3485, If inputs are unconnected(floating),

   The receiver contains a fail safe feature that result in as logic high output state.

   And when inputs are OPEN, RO should output "1"(3.3V).  But ADM3485 seems not following it.

   Regarding above measuring results, 

   The ADM3485E is with 1.8V logic high state and output normal RO=3.3V value.

    The ADM3485 is not with 1.8V logic high state and output abnormal RO=0V value.

    Please help to reply why the RO, A, B of ADM3485 in inputs open did not follow

    it's data sheet spec.   Thanks!


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