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AM5706: About absolute maximum ratings when power is not supplied

O.H
Mastermind 6260 points
Part Number: AM5706

Hi experts,

Currently, my customer is considering AM5706, so let me check the absolute maximum ratings.

Q1:As for the absolute maximum voltage rating for each ball, is it correct to say that there is no need to worry about failures as long as "VIO (Steady-State)" is satisfied regardless of the state of the SoC?

Q2:For example, the AC5/AB6 communicates with external devices via USB2.0. Is it safe to assume that there is no risk of failure if USB2.0 signals are input from external devices while the SoC power is turned off?

Q3:Could you tell me the meaning of "Steady-State"? They would also like to understand the meaning of "Steady-State" correctly.

For example, in AM437x and AM335x, "Steady state max voltage at all I/O pins" is described as shown in the figure below, and "-0.5V to I/O supply voltage + 0.3V", so it is expected that there will be a problem in case Q2. However, the upper limit of the rated voltage for the AM57x is listed as "~*.*V" instead of "I/O supply voltage + 0.3 V", so there should be no problem in case Q2.

Best regards,
O.H

  • 0
    Mastermind 6260 points

    Hi,

    Could you tell us about your current situation?

    Customers are looking for answers, so it would be helpful if you could just tell us the situation.

    Best regards,
    O.H

  • 0 in reply to O.H
    Mastermind 6260 points

    Hi,

    Sorry, I didn't check the datasheet enough for Q1. From the note (7) in the datasheet "5.1 Absolute Maximum Ratings", I judged that there is a risk of damage when the SoC power supply is turned off completely.

    (7) The maximum valid input voltage on an IO pin cannot exceed 0.3 volts when the supply powering the IO is turned off. This requirement applies to all the IO pins which are not fail-safe and for all values of IO supply voltage. Special attention should be applied anytime peripheral devices are not powered from the same power sources used to power the respective IO supply. It is important the attached peripheral never sources a voltage outside the valid input voltage range, including power supply ramp-up and ramp-down sequences.

    The AC5/AB6 uses USB2.0 to communicate with the IC on a different board, but I think there are cases where external devices are usually connected to the USB port when the power is off. Therefore, it would be helpful if you could answer Q2. (For example, the USB port is an exception.)

    Best regards,
    O.H