WM8973LGEFL/V Wolfson Microelectronics, WM8973LGEFL/V Datasheet - Page 55

• Manufacturer Part Number: WM8973LGEFL/V
• Description: Audio CODECs Stereo Codec with H/P Spkr
• Manufacturer: Wolfson Microelectronics

Specifications of WM8973LGEFL/V

• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Package / Case: QFN-32
• Minimum Operating Temperature: - 25 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Advanced Information
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OPERATION MODE
Stereo Headphone Playback
Stereo Line-in Record
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]
MINIMISING POP NOISE AT THE ANALOGUE OUTPUTS
POWER MANAGEMENT EXAMPLES
Table 46 Register Settings for Power Management
The recommended application circuit is shown above. R1 and R2 form part of the biasing network
(refer to Microphone Bias section). R1 connected to MICBIAS is necessary only for electret type
microphones that require a voltage bias. R2 should always be present to prevent the microphone
input from charging to a high voltage which may damage the microphone on connection. R1 and R2
should be large so as not to attenuate the signal from the microphone, which can have source
impedance greater than 2kOhm. C1 together with the source impedance of the microphone and the
WM8973L input impedance forms an RF filter. C2 is a DC blocking capacitor to allow the microphone
to be biased at a different DC voltage to the MICIN signal.
To minimise any pop or click noise when the system is powered up or down, the following procedures
are recommended.
POWER UP
POWER DOWN
Switch on power supplies. By default the WM8973L 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, then wait for time TBD
Enable DACs as required
Enable line and / or headphone output buffers as required.
Set DACMU = 0 to soft-un-mute the audio DACs.
Set DACMU = 1 to soft-mute the audio DACs.
Disable all output buffers, then wait for time TBD.
Switch off the power supplies.
1
1
1
1
1
1
1
1
POWER MANAGEMENT (1)
1
1
1
1
1
1
1
1
PGL PGR ADL ADR
0
1
1
1
0
1
1
1
PGAs
0
1
1
0
0
0
0
1
0
1
1
1
0
0
0
1
ADCs
0
1
1
0
0
0
0
1
MBI
0
0
1
1
0
1
1
1
DAL DAR LO1
1
0
0
0
0
0
0
0
DACs
1
0
0
0
0
0
0
0
POWER MANAGEMENT (2)
1
0
0
0
1
1
0
1
RO1
1
0
0
0
1
1
0
1
Output Buffers
AI Rev 3.2 July 2004
LO2
0
0
0
0
0
0
1
0
WM8973L
RO2
0
0
0
0
0
0
1
0
MO
0
0
0
0
0
1
1
1
HPD
55
x
0
0
0
x
x
0
x