CS4297-KQ Cirrus Logic, CS4297-KQ Datasheet - Page 33

• Manufacturer Part Number: CS4297-KQ
• Description: CrystalClear SoundFusion Audio Codec 97
• Manufacturer: Cirrus Logic

DS242F5
GROUNDING AND LAYOUT
Figure 10 is the suggested layout for the CS4297.
The decoupling capacitors should be located phys-
ically as close to the pins as possible. Also note the
routing of the REFFLT decoupling capacitors and
the isolation of that ground strip.
It is strongly recommended that the device be locat-
ed on a locally separate analog ground plane. This
analog ground plane is used to keep noise from dig-
ital ground return currents from modulating the
CS4297’s ground potential and degrading perfor-
mance. The digital ground pins should be connect-
CS4297
CrystalClear™ SoundFusion™ Audio Codec ’97
To +5VA
0.1 µF
Y5V
AVss2
DVdd1
Figure 10. Suggested Layout for the CS4297
To +5VD
Pin 1
AVdd2
0.1 µF
Y5V
To Analog
Ground
To Digital Ground
AFLT2
390 pF
NPO
DVss2
ed to the digital ground plane and kept separate
from the analog ground connections of the CS4297
and any other external analog circuitry.
It is also recommended that the common connec-
tion point between the two ground planes (required
to maintain a common ground voltage potential) be
located near the CS4297 just under the digital
ground connections (vias). The AC-Link digital in-
terface connection traces should be routed such that
digital ground plane lies underneath these signals
(on the internal ground layer) from the AC’97 Con-
troller continuously to the CS4297.
DVss1
Analog Ground
AFLT1
Vrefout
to via
REFFLT
0.1 µF
Y5V
AVss1 AVdd1
DVdd2
To +5VD
1 µF
To Analog
Ground
To +5VA
0.1 µF
Y5V
33