WM8750L
Production Data
MINIMISING POP NOISE AT THE ANALOGUE OUTPUTS
To minimise any pop or click noise when the system is powered up or down, the following procedures
are recommended.
POWER UP
Switch on power supplies. By default the WM8750L is in Standby Mode, the DAC is digitally
muted and the Audio Interface, Line outputs and Headphone outputs are all OFF (DACMU
= 1 Power Management registers 1 and 2 are all zeros).
Enable Vmid and VREF.
Enable DACs as required
Enable line and / or headphone output buffers as required.
Set DACMU = 0 to soft-un-mute the audio DACs.
POWER DOWN
Set DACMU = 1 to soft-mute the audio DACs.
Disable all output buffers.
Switch off the power supplies.
POWER MANAGEMENT EXAMPLES
OPERATION MODE
POWER MANAGEMENT (1)
PGAs ADCs
POWER MANAGEMENT (2)
DACs
Output Buffers
PGL PGR ADL ADR MBI DAL DAR LO1 RO1 LO2 RO2 MO HPD
Stereo Headphone Playback
Stereo Line-in Record
1
1
1
1
1
1
1
1
0
1
1
1
1
1
1
1
0
1
1
1
0
1
1
1
0
1
1
0
0
0
0
1
0
1
1
1
0
0
0
1
0
1
1
0
0
0
0
1
0
0
1
1
0
1
1
1
1
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
1
0
0
0
1
1
0
1
1
0
0
0
1
1
0
1
0
0
0
0
0
0
1
0
0
0
0
0
0
0
1
0
0
0
0
0
0
1
1
1
x
0
0
0
x
x
0
x
Stereo Microphone Record
Mono Microphone Record
Stereo Line-in to Headphone Out
Phone Call
Speaker Phone Call [ROUT2INV = 1]
Record Phone Call [L channel = mic with
boost, R channel = RX, enable mono mix]
Table 49 Register Settings for Power Management
PD, Rev 4.4, August 2012
62
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WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
