WM8903LGEFK/RV Wolfson Microelectronics, WM8903LGEFK/RV Datasheet - Page 53

• Manufacturer Part Number: WM8903LGEFK/RV
• Description: Audio CODECs ULTRA LOW PWR HI FI CODEC
• Manufacturer: Wolfson Microelectronics

Specifications of WM8903LGEFK/RV

• Audio Codec Type: Stereo Codec
• No. Of Adcs: 2
• No. Of Dacs: 2
• No. Of Input Channels: 6
• No. Of Output Channels: 8
• Adc / Dac Resolution: 24bit
• Sampling Rate: 96kHz
• Operating Temperature Range: -40°C To +85°C
• Rohs Compliant: Yes
• Adcs / Dacs Signal To Noise Ratio: 96dB
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Pre-Production
Figure 32 DAC Mute Control
w
DAC SOFT MUTE AND SOFT UN-MUTE
The WM8903 has a soft mute function. When enabled, this gradually attenuates the volume of the
DAC output. When soft mute is disabled, the gain will either gradually ramp back up to the digital
gain setting, or return instantly to the digital gain setting, depending on the DAC_MUTEMODE
register bit.
The DAC is not muted by default (DAC_MUTE = 0). To mute the DAC, this function must be enabled
by setting DAC_MUTE to 1.
Soft Mute Mode would typically be enabled (DAC_MUTEMODE = 1) when using DAC_MUTE during
playback of audio data so that when DAC_MUTE is subsequently disabled, the sudden volume
increase will not create pop noise by jumping immediately to the previous volume level (e.g.
resuming playback after pausing during a track).
Soft Mute Mode would typically be disabled (DAC_MUTEMODE = 0) when un-muting at the start of a
music file, in order that the first part of the track is not attenuated (e.g. when starting playback of a
new track, or resuming playback after pausing between tracks).
The volume ramp rate during soft mute and un-mute is controlled by the DAC_MUTERATE bit.
Ramp rates of fs/32 and fs/2 can be selected, as shown in Table 29. The ramp rate determines the
rate at which the volume is increased or decreased. The actual ramp time depends on the extent of
the difference between the muted and un-muted volume settings.
Table 29 DAC Soft-Mute Control
R33 (21h)
DAC Digital 1
REGISTER
ADDRESS
BIT
10
9
3
DAC_MUTERA
TE
DAC_MUTEM
ODE
DAC_MUTE
LABEL
DAC muting and un-muting using volume control bits
DACL_VOL and DACR_VOL.
DAC
DAC_MUTE.
Soft Mute Mode not enabled (DAC_MUTEMODE = 0).
DAC
DAC_MUTE.
Soft Mute Mode enabled (DAC_MUTEMODE = 1).
muting
muting
DEFAULT
0
0
0
and un-muting using soft mute
and un-muting using soft mute
DAC Soft Mute Ramp Rate
0 = Fast ramp (fs/2, maximum ramp
time is 10.7ms at fs=48k)
1 = Slow ramp (fs/32, maximum ramp
time is 171ms at fs=48k)
DAC Soft Mute Mode
0 = Disabling soft-mute
(DAC_MUTE=0) will cause the DAC
volume to change immediately to
DACL_VOL and DACR_VOL settings
1 = Disabling soft-mute
(DAC_MUTE=0) will cause the DAC
volume to ramp up gradually to the
DACL_VOL and DACR_VOL settings
DAC Soft Mute Control
0 = DAC Un-mute
1 = DAC Mute
DESCRIPTION
PP, Rev 3.1, August 2009
WM8903
bit
bit
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