wm9712l Wolfson Microelectronics plc, wm9712l Datasheet - Page 72

• Manufacturer Part Number: wm9712l
• Description: Ac?97 Audio And Touchpanel Codec
• Manufacturer: Wolfson Microelectronics plc

WM9712L
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RECOMMENDED COMPONENTS VALUES
Table 46 External Components Descriptions
Note:
1. For Capacitors C7, C8, C10, C12 and C14 it is recommended that very low ESR components are used.
LINE OUTPUT
COMPONENT
REFERENCE
C27 & C28
C15 - C20
C21 - C23
C24 - C26
C1 - C6
C7 - C8
C10
C11
C12
C13
C14
C9
R1
R2
XT
SUGGESTED
24.576MHz
VALUE
100kΩ
100kΩ
100nF
100nF
100nF
100nF
220µF
2.2uF
10uF
10uF
10uF
10uF
22pF
1uF
The headphone outputs, HPOUTL and HPOUTR, can be used as stereo line outputs. The speaker
outputs, LOUT2 and ROUT2, can also be used as line outputs, if LOUT2 is not inverted for BTL
operation (INV = 0). Recommended external components are shown below.
Figure 24 Recommended Circuit for Line Output
The DC blocking capacitors and the load resistance together determine the lower cut-off frequency,
fc. Assuming a 10 kΩ load and C1, C2 = 10µF:
fc = 1 / 2π (R
Increasing the capacitance lowers fc, improving the bass response. Smaller values of C1 and C2 will
diminish the bass response. The function of R1 and R2 is to protect the line outputs from damage
when used improperly.
WM9712L
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DESCRIPTION
De-coupling for VREF
De-coupling for DBVDD,DCVDD,TPVDD,AVDD,SPKVDD,HPVDD
Reservoir capacitor for DVDD, AVDD. Should the supplies use separate sources then
additional capacitors will be required of each additional source.
De-coupling for CAP2.
Reservoir capacitor for CAP2
Reservoir capacitor for VREF
De-coupling for MICBIAS - Not required if MICBIAS output is not used
Reservoir capacitor for MICBIAS - Not required if MICBIAS output is not used
Required when used with a parallel resonant crystal.
AC coupling capacitors
Output AC coupling capacitors to remove VREF DC level from outputs
Output AC coupling capacitors to remove VREF DC level from outputs.
Pull-up resistor, ensures that all circuit blocks are OFF by default
Pull down resistor, ensures that all circuit blocks are ON by default
AC'97 master clock frequency. A bias resistor is not required but if connected will not
affect operation if the value is large (above 1MΩ)
+R
1
) C
HPOUTR /
HPOUTL /
ROUT2
LOUT2
1
= 1 / (2π x 10.1kΩ x 1µF) = 16 Hz
1uF
1uF
C1
C2
100 Ohm
100 Ohm
R1
R2
HPGND
HPGND
LINE-OUT
LINE-OUT
SOCKET
SOCKET
(RIGHT)
(LEFT)
PD Rev 4.5 August 2006
Production Data
72