The ADV7611 datasheet includes requirements concerning sequencing of 3.3 and 1.8 power supplies.
Though there are ways to control the Power Up sequence to fit the requirement (3.3 always `above' 1.8)
it is not that easy for Powert Down.
Could you please clarify this requirement in more detail ?
(especially but not only for Power Down)
What are the consequences when violiating this requirement ?
-) a parasitic diode will conduct current from 1.8 to 3.3 ?
-) which might destroy the chip, if X mA is conducted for more than Y ms ?
-) latch up will occur, and might prohibit another startup for Z ms ?
.-) internal startup will fail ?, and can't be forced with #RESET,
because #RESET is not really a #RESET, but more
a sort of RESET-Rrequest, which won't always be honoured ?
-) some fets gate will be stressed and might shift its threshold ?
-) any other issues ?
Any Ideas how to design a low cost power supply which fullfills this requirement ?