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maximum voltage safe for ADUM1401 inputs during power down(VDD=0V)

Question asked by LarryD on Apr 6, 2016
Latest reply on Apr 7, 2016 by LarryD

Hello,

 

The datasheet say the allowed maximum voltage on ADUM1401 inputs are VDD+0.5V.  It looks only +0.5V is allowed on inputs when VDD is down(VDD=0V).

Could anyone pls advice whether a series resistor to limit the current into the inputs will allow a voltage bigger than 0.5V(like 5V) applied on inputs when VDD=0V?    I mean, a voltage safe for ADUM1401's reliable operation.

If this is feasible, what is the current limit?   Thanks in advance.

 

My application is like this: a ADUM1401B is used to isolate some digital outputs. It is powered by an isolated 5V supply(VDD1).  Its D channel (VID) is used to feedback a 5V signal to MCU side.  There are some cases that VDD1 is down but that 5V signal is still applied on Pin VID.     

 

Larry

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