CS4228 Datasheet, PDF (18/30 Pages) Cirrus Logic – 24-Bit, 96 kHz Surround Sound Codec

CS4228
The CS4228 will mute the analog outputs, assert
the MUTEC pin and enter the Power Down Mode
if the supply drops below approximately 4 volts.
Power Supply, Layout, and Grounding
The CS4228 requires careful attention to power
supply and grounding details. VA is normally sup-
plied from the system analog supply. VD is from a
3.3VDC supply, and VL should be from the supply
used for the devices digitally interfacing with the
CS4228. The power up sequence of these three
supply pins is not important.
AGND and DGND pins should both be tied to a
solid ground plane surrounding the CS4228. If the
system analog and digital ground planes are sepa-
rate, they should be connected at a point near where
the supply currents enter the board. A solid ground
plane underneath the part is recommended.
Decoupling capacitors should be mounted in such a
way as to minimize the circuit path length from the
CS4228 supply pin, through the capacitor, to the
applicable CS4228 AGND or DGND pin. The
small value ceramic capacitors should be closest to
the part. In some cases, ferrite beads in the VL, VD
and VA supply lines, and low-value resistances
(~ 50 Ω) in series with the LRCK, SCLK, and SD-
OUT lines can help reduce coupling of digital sig-
nals into the analog.
The capacitor on the FILT pin should be as close to
the CS4228 as possible. See Crystal’s layout Appli-
cations Note, and the CDB4228 evaluation board
data sheet for recommended layout of the decou-
pling components.
18
DS307PP1