WM8731 Wolfson Microelectronics Ltd., WM8731 Datasheet - Page 25

• Manufacturer Part Number: WM8731
• Description: WM8731 : Low Power Audio Codec With Integrated Headphone Driver
• Manufacturer: Wolfson Microelectronics Ltd.

WM8731
Figure 16 DAC Filter Schematic
The DAC digital filter can apply digital de-emphasis under software control, as shown in Table 6.The
DAC can also perform a soft mute where the audio data is digitally brought to a mute level. This
removes any abrupt step changes in the audio that might otherwise result in audible clicks in the
audio outputs.
Table 6 DAC Software Control
DAC
The WM8731 employs a multi-bit sigma delta oversampling digital to analogue converter. The
scheme for the converter is illustrated in Figure 17.
Figure 17 Multi-Bit Oversampling Sigma Delta Schematic
The DAC converts the multi-level digital audio data stream from the DAC digital filters into high
quality analogue audio.
0000101
Digital
Audio Path
Control
REGISTER
ADDRESS
FROM DIGITAL
INTERFACE
AUDIO
FROM DAC
FILTERS
DIGITAL
2:1
3
BIT
DE_EMPHASIS
DEEMP
DIGITAL
DEEMP[1:0]
DACMU
LABEL
DACMU
MUTE
00
1
DEFAULT
INTERPOLATION
DIGITAL
FILTER
TO LINE OUTPUT
De-emphasis Control
(Digital)
11 = 48kHz
10 = 44.1kHz
01 = 32kHz
00 = Disable
DAC Soft Mute Control
(Digital)
1 = Enable soft mute
0 = Disable soft mute
AI Rev 2.3 August 2001
DESCRIPTION
OUTPUTS
TO LINE
Advanced Information
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