CS4294 Datasheet, PDF (32/42 Pages) Cirrus Logic – SoundFusion Audio/Docking Codec 97 (AMC 97)

CS4294
ALT_LINE_OUT_R
ALT_LINE_OUT_L
Vrefout
1
4
2
3
27kΩ
680pF 680pF
NPO NPO
AGND
0.1µF
Y5V
1.0µF
Y5V
AGND
2_-
3₊
TDA1308
1
22pF
NPO
1
4
2
3
39kΩ
22pF
6_-
5₊
NPO
7
TDA1308
220µF
+
ELEC
220µF
+
ELEC
10Ω
1/4 WATT
10Ω
1/4 WATT
43
47KΩ
12
HP_OUT_R
HP_OUT_L
AGND
Figure 13. Headphones Driver
7.5 Power Supplies
The power supplies providing analog power should
be as clean as possible to minimize coupling into
the analog section which could degrade analog per-
formance. The pins AVdd1 and AVdd2 supply
power to all the analog circuitry on the CS4294.
This 5 Volt analog supply should be generated
from a voltage regulator (7805 type) connected to a
+12 Volt supply. This helps isolate the analog cir-
cuitry from noise typically found on +5 V digital
supplies which power many digital circuits in a PC
environment. A typical voltage regulator circuit for
analog power using an MC78M05CDT is shown in
Figure 14.
The digital power pins DVdd1 and DVdd2 should
be connected to the same digital supply as the AC
’97 Controller’s AC-Link interface. Since the digi-
tal interface on the CS4294 may operate at either
3.3 V or 5 V, proper connection of these pins will
depend on the digital power supply of the AC ’97
Controller. connections (vias). The AC-Link digi-
tal interface connection traces should be routed
such that digital ground plane lies underneath these
signals (on the internal ground layer) from the AC
’97 Controller continuously to the CS4294.
+12VD
MC78M05CDT
Y5V
0.1µF
1 _IN
+ _ELEC
10µF
OUT ³
GND
2
Y5V
0.1µF
+5VA
+ _ELEC
10µF
DGND
Figure 14. Voltage Regulator
AGND
32
DS326PP4