WM8974GEFL/V Wolfson Microelectronics, WM8974GEFL/V Datasheet - Page 17

• 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 2 Auxiliary Input Buffer Control
INPUT BOOST
Table 3 Input BOOST Stage Control
In mixer mode (AUXMODE=1) the on-chip input resistor is bypassed, this allows the user to sum in
multiple inputs with the use of external resistors.
variations through this path from part to part due to the variation of the internal 20kΩ resistors
relative to the higher tolerance external resistors.
The input BOOST circuit has 3 selectable inputs: the input microphone PGA output, the AUX
amplifier output and the MICP input pin (when not using a differential microphone configuration).
These three inputs can be mixed together and have individual gain boost/adjust as shown in Figure
8.
The input PGA path can have a +20dB boost (PGABOOST=1) a 0dB pass through (PGABOOST=0)
or be completely isolated from the input boost circuit (INPPGAMUTE=1).
The Auxiliary amplifier path to the BOOST stage is controlled by the AUX2BOOSTVOL[2:0] register
bits.
Settings 001 through to 111 control the gain in 3dB steps from -12dB to +6dB.
Figure 8 Input Boost Stage
R1
Power
management 1
R44
Input control
R45
Input PGA gain
control
R47
Input BOOST
control
REGISTER
REGISTER
ADDRESS
ADDRESS
When AUX2BOOSTVOL=000 this path is completely disconnected from the BOOST stage.
6
3
6
8
BIT
BIT
AUXEN
AUXMODE
INPPGAMUTE
PGABOOST
LABEL
LABEL
0
0
DEFAULT
0
0
DEFAULT
When used in this mode there will be gain
Auxiliary input buffer enable
0 = OFF
1 = ON
0 = inverting buffer
1 = mixer (on-chip input resistor bypassed)
Mute control for input PGA:
0=Input PGA not muted, normal operation
1=Input PGA muted (and disconnected from the
following input BOOST stage).
0 = PGA output has +0dB gain through input
BOOST stage.
1 = PGA output has +20dB gain through input
BOOST stage.
PD, Rev 4.5, September 2008
DESCRIPTION
DESCRIPTION
WM8974
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