i.MX8DXP monotonic input transition

[RobertoVigliarolo]

Hi community,

I noted that in this data sheet IMX8QXPAEC (Rev. 3) there are many notes (note 3 or 4) related to Vih/Vil specifications:
"To maintain a valid level, the transition edge of the input must sustain a constant slew rate (monotonic) from the current DC level through to the target DC level, VIL or VIH. Monotonic input transition time is from 0.1 ns to 1 ns."

I am designing a new board using MiMX8DX1AVLFZAC and I have HUGE difficulties complying to these notes. I think that something need to be corrected and below I explain why I think so.

1. maintaining a strictly constant slew rate using normal CMOS stage is impossible. A better wording can be "...the transition edge of the input between Vil and Vih must be monotonic and between Vil and Vih the absolute value of slew rate must be always more than x mV/ns" (I think 100 mV/ns could be OK)
2. This sentence: "Monotonic input transition time is from 0.1 ns to 1 ns." should be removed or changed to "Input transition time between Vil and Vih, or vice versa, must be from 0.1 ns to x ns" (I think 25 ns could be OK: please consider that many interface circuit (CAN, RS485, I/O expander, etc.) or analog components (ADC, DAC, etc.) have slow transition times.

Best regards,

Roberto Vigliarolo

[AldoG]

Hello,

I have contacted team regarding this and shared your concerns with them, they plan to update data sheet in April.

Concerning I/O rise/fall times and slew rates, MX8 series devices meet standards specs as listed in the reference manuals, such as uSDHC, Sim, HDMI, ENET, etc.

Best regards,
Aldo.