Hello,
The part in question is the DP83867ERGZR.
According to the datasheet:
“When operating in three-supply mode, the 1.8-V VDDA1P8 supply must be stable within 25 ms of the 2.5-V VDDA2P5 supply ramping up. There is no sequencing requirement for other supplies when operating in three supply mode.
When powering down the DP83867, the 1.8-V supply should be brought down before the 2.5-V supply.”
There is a note that reads: “If the 2.5-V power supply provides power to DP83867 devices only, the 1.8-V supply may ramp up any time before 2.5-V.”
In my design, the 2.5-V supply feeds the Xtal connected to the X_I pin and other devices that are not related to the DP83867ERGZR.
Does the above note still apply? That is, can I bring the 1.8-V supply up first, and then the 2.5-V supply?
If the note is valid, do I still need to power down first the 1.8-V supply before the 2.5-V supply, or can I power down first the 2.5-V supply and then the 1.8-V supply?
Thanks for your help, appreciated.
Victor
