Post Go back to editing

when the ADIN1200 is powered off

Category: Datasheet/Specs
Product Number: ADIN1200

When the device in which the ADIN1200 is installed is turned off, that is, when the ADIN1200 is powered off,

I think that there is a state in which voltage is applied to the MDI_x_x terminals from other powered devices via cables and pulse transformers.

Q1 In the above state, it is thought that the maximum absolute rating of the MDI_x_x terminal ~ AVDD_3P3 + 0.3V will be exceeded, but is it NG?

Q2 If you have any advice on countermeasures, please let me know

Parents Reply Children
  • thank you for your answer.
    I understand not to destroy it.
    However, when the power is turned off, the communication signal from the opposing machine will exceed the maximum absolute rating, so it is not guaranteed?

  • Hi,

    There is protection circuitry internal to the MDI pins which will protect them when standard ethernet traffic is sent into an unpowered device.

    Best Regards,

    Mark

  • thank you for your answer.
    Does the protection circuit mean that it is a circuit that suppresses the maximum absolute rating (0.3V because the power is not on) or less? Or is it OK to exceed the maximum absolute rating for a short period of time?

  • Yes in that case the ABS MAX rating is 0.3V, which is the highest DC voltage that can be constantly applied to the pin. The protection circuitry will project the devices against transients greater than this value for a short period of time.

  • thank you for your answer.

    To summarize,
    The signal coming from other powered devices via cables and pulse transformer when the power is off will exceed the maximum absolute rating of 0.3V in this state.
    However, there is a protection circuit that does not break even if the maximum absolute rating is exceeded for a short time, so it will not break for a short time.

    According to the current data sheet description method, this usage is not broken, but it can be read as out of warranty(because exceed he maximum absolute rating).
     I request to change the description in the datasheet (for example, ●●mS may exceed the maximum absolute rating).