WM8974GEFL/V Wolfson Microelectronics, WM8974GEFL/V Datasheet - Page 45

• Manufacturer Part Number: WM8974GEFL/V
• Description: Audio CODECs Mono Codec with Spkr
• Manufacturer: Wolfson Microelectronics

Specifications of WM8974GEFL/V

• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Package / Case: QFN-24
• Minimum Operating Temperature: - 25 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Production Data
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Table 41 Mono Mixer Control
ENABLING THE OUTPUTS
Table 42 Output Stages Power Management Control
UNUSED ANALOGUE INPUTS/OUTPUTS
Each analogue output of the WM8974 can be separately enabled or disabled. The analogue mixer
associated with each output has a separate enable. All outputs are disabled by default. To save
power, unused parts of the WM8974 should remain disabled.
Outputs can be enabled at any time, but it is not recommended to do so when BUFIO is disabled
(BUFIOEN=0), as this may cause pop noise (see “Power Management” and “Applications
Information” sections).
Whenever an analogue input/output is disabled, it remains connected to a voltage source (either
AVDD/2 or 1.5xAVDD/2 as appropriate) through a resistor. This helps to prevent pop noise when the
output is re-enabled. The resistance between the voltage buffer and the output pins can be
controlled using the VROI contol bit. The default impedance is low, so that any capacitors on the
outputs can charge up quickly at start-up. If a high impedance is desired for disabled outputs, VROI
can then be set to 1, increasing the resistance to about 30kΩ.
R56
Mono mixer control
R40
Bypass path
attenuation control
R1
Power
management 1
R3
Power
management 3
Note: All “Enable” bits are 1 = ON, 0 = OFF
REGISTER
ADDRESS
REGISTER
ADDRESS
2
8
3
2
3
5
6
7
BIT
BIT
0
1
2
6
2
BUFIOEN
BUFDCOPEN
BIASEN
SPKMIXEN
MONOMIXEN
SPKPEN
SPKNEN
MONOEN
DAC2MONO
BYP2MONO
AUX2MONO
MONOMUTE
MONOATTN
LABEL
LABEL
0
0
0
0
0
0
0
0
DEFAULT
DEFAULT
0
0
0
0
0
Unused input/output tie off buffer enable
Output stage 1.5xAVDD/2 driver enable
Analogue amplifiers bias enable
Speaker Mixer enable
Mono mixer enable
SPKOUTP enable
SPKOUTN enable
MONOOUT enable
Output of DAC to mono mixer input
0 = not selected
1 = selected
Bypass path (output of input boost stage) to
mono mixer input
0 = non selected
1 = selected
Output of Auxiliary amplifier to mono mixer
input:
0 = not selected
1 = selected
0=No mute
1=Output muted. During mute the mono
output will output VMID which can be used
as a DC reference for a headphone out.
Attenuation control for bypass path (output
of input boost stage) to mono mixer input
0 = 0dB
1 = -10dB
PD, Rev 4.5, September 2008
DESCRIPTION
DESCRIPTION
WM8974
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