WM8711 Wolfson Microelectronics Ltd., WM8711 Datasheet - Page 12

• Manufacturer Part Number: WM8711
• Description: Internet Audio DAC With Integrated Headphone Driver
• Manufacturer: Wolfson Microelectronics Ltd.

WM8711
WOLFSON MICROELECTRONICS LTD
Figure 8 Line Output Schematic
The line output is muted by either muting the DAC (analogue) or Soft Muting (digital) and disabling
the BYPASS path. Refer to the DAC section for more details. Whenever the DAC is muted or the
device placed into standby mode the DC voltage is maintained at the line outputs to prevent any
audible clicks from being present.
The software control for the line outputs is shown in Table 3.
Table 3 Output Software Control
The recommended external components are shown in Figure 9.
Figure 9 Line Outputs Application Drawing
Recommended values are C1 = 470nF (10V npo type), R1 = 47KOhms, R2 = 100 Ohms
C1 forms a DC blocking capacitor to the line outputs. R1 prevents the output voltage from drifting so
protecting equipment connected to the line output. R2 forms a de-coupling resistor preventing
abnormal loads from disturbing the device. Note that poor choice of dielectric material for C1 can
have dramatic effects on the measured signal distortion at the output.
0000100
Analogue
Audio Path
Control
REGISTER
ADDRESS
FROM LINE
FROM DAC
INPUTS
LINEOUT
BIT
3
4
BYPASS
DACSEL
LABEL
C1
DACSEL
BYPASS
VMID
AGND
DEFAULT
1
0
R1
R2
Bypass Switch
1 = Enable Bypass
0 = Disable Bypass
DAC Select
1 = Select DAC
0 = Don’t select DAC
PP Rev 1.2 November 2000
DESCRIPTION
AGND
TO HEADPHONE AMP
LINEOUT
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