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Original question:

AM3357: Transient overshoot and undershoot

AM3352: overshoot in reset

Sung-IL
Mastermind 30810 points
Part Number: AM3352

Dear Champs,

My customer found an overshoot in reset signal(PWRONRSTn pin) of AM3352, and I would check with  you if this overshoot is OK or not.

My customer observed 0.39V overshoot(e.g. 3.69V overshoot as 3.3V IO supply used).

From below e2e and Table5.1 of Datasheet, it seemed it is allowed for overshoot up to 25% of corresponding IO supply voltage and thus it is OK not to exceed 25% of IO supply voltage. Does my understanding right?

https://e2e.ti.com/support/processors/f/791/t/709992?tisearch=e2e-sitesearch&keymatch=overshoot

For RESET signal, how we calculate duration?(e.g. 30% of signal period in the datasheet)

My customer measured overshoot as below, and the scale was normalized and they confirmed the peak of overshoot is 3.69V.

Thanks and Best Regards,

SI.

  • 0
    TI__Genius 15900 points

    Hi SI,

    Channel 3 in the scope shot appears to increase to ~400 mV, fall back to ~150 mV, and then (in the zoomed out view at the top of the screen shot) jump to 3.3V.

    The overshoot described in the Absolute Max table occurs when the rail exceeds VDD.  I do not see this behavior in the scope shot provided.

    Regards,

    Melissa