The datasheet states on pg. 56 that “The 1.8 V supplies should be enabled prior to
enabling the 3.3 V supplies. Do not enable the 3.3 V supplies when the 1.8 V
supplies are off.”
There is no guidance here as far as time required between the ramp up of the +1.8Vdc
supply relative to the +3.3Vdc supply. What is the time requirement between the
ramp up of the two power supplies? Or is it some relationship we need to
satisfy (i.e. the +3.3Vdc should not begin ramping until the +1.8Vdc has
reached 90% of its nominal value)?
Please advise when you can - thanks.