using ferrite bead or resistor between the AGND and DGND

[vijaya_narayana]

hi every body

i know that a ferrite bead or a resistor is used to couple the analogue ground and digital ground in schematic and in layout .
could anybody pls explain me y we are using a resistor or ferrite bead to couple the same in detail



vijay

 

[Surender Reddy]

It is better to use to ferrite bead, because ferrite bead doesn't allow ac ripples and digital ground doesn't have ac ripples.
So ferrite bead is the good option.