CS4294 Cirrus Logic, CS4294 Datasheet - Page 32

• Manufacturer Part Number: CS4294
• Description: SoundFusion Audio/Docking Codec 97 (AMC 97)
• Manufacturer: Cirrus Logic

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
32
Vrefout
ALT_LINE_OUT_R
ALT_LINE_OUT_L
Y5V
0.1 F
680pF
NPO
AGND
AGND
680pF
NPO
1
2
1.0 F
Y5V
27k
Figure 13. Headphones Driver
4
3
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.
2
3
1
2
6
5
Y5V
0.1µF
-
+
-
+
DGND
22pF
NPO
22pF
+12VD
NPO
TDA1308
TDA1308
39k
4
3
+
Figure 14. Voltage Regulator
ELEC
10µF
1
7
1
IN
ELEC
220 F
220 F
ELEC
MC78M05CDT
+
+
GND
2
AGND
4
1 2
3
OUT
1/4 WATT
1/4 WATT
47K
10
10
3
Y5V
0.1µF
HP_OUT_R
HP_OUT_L
CS4294
DS326PP4
+5VA
AGND
+
ELEC
10µF