ADU4160 - How long does PIN (pin 12) need to be brought low to re-enumerate the connection?

The system I am working on has ESD susceptibility issues. The communication channel between the host and the peripheral becomes disabled due to ESD events. I have found that I bring the PIN line (pin 12  on the ADUM4160) low using a pushbutton, the channel re-enumerates. I'd like to have the peripheral microcontroller do this and I'd like to know the minimum amount of time the PIN line needs to be brought low.

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  • +1
    •  Analog Employees 
    on Nov 26, 2020 5:14 PM 1 month ago in reply to timambrose

    Hi timambrose,

    Applying low to PIN will remove power from the 1.5k upstream pull-up (on UD+ for full-speed, on UD- for low speed). There is the propagation delay for this input on side 2 to affect side 1 (upstream); which isn't specified for ADuM4160, but this delay will be short compared to how long the pull-up must remain unpowered for the host to detect the condition as "unplugged" and then be ready to detect the ADuM4160 again once PIN is high.

    5 ms may be too short for some hosts to detect the condition; you might want to consider the specific hosts (micros) you expect, but 10 ms or even longer might be a good idea to make sure the disconnect is detected. I recommend a search to see what's common for processor/software response times to an "unplug" event.

    External ESD protection would be recommended for ADuM4160 in order to maintain normal operation, this might avoid the need to essentially power-cycle part of the upstream/port side of the ADuM4160.

    Best regards,

    Conal

Reply
  • +1
    •  Analog Employees 
    on Nov 26, 2020 5:14 PM 1 month ago in reply to timambrose

    Hi timambrose,

    Applying low to PIN will remove power from the 1.5k upstream pull-up (on UD+ for full-speed, on UD- for low speed). There is the propagation delay for this input on side 2 to affect side 1 (upstream); which isn't specified for ADuM4160, but this delay will be short compared to how long the pull-up must remain unpowered for the host to detect the condition as "unplugged" and then be ready to detect the ADuM4160 again once PIN is high.

    5 ms may be too short for some hosts to detect the condition; you might want to consider the specific hosts (micros) you expect, but 10 ms or even longer might be a good idea to make sure the disconnect is detected. I recommend a search to see what's common for processor/software response times to an "unplug" event.

    External ESD protection would be recommended for ADuM4160 in order to maintain normal operation, this might avoid the need to essentially power-cycle part of the upstream/port side of the ADuM4160.

    Best regards,

    Conal

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