wm8952 Wolfson Microelectronics plc, wm8952 Datasheet - Page 18

• Manufacturer Part Number: wm8952
• Description: Mono Adc With Microphone Pre-amplifier
• Manufacturer: Wolfson Microelectronics plc

WM8952
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INPUT BOOST
Table 6 Input BOOST Stage Control
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.
The MICP path to the BOOST stage is controlled by the MICP2BOOSTVOL[2:0] register bits.
When MICP2BOOSTVOL=000 this input pin is completely disconnected from the BOOST stage.
Settings 001 through to 111 control the gain in 3dB steps from -12dB to +6dB.
Figure 8 Input Boost Stage
R45
Input PGA gain
control
R47
Input BOOST
control
REGISTER
ADDRESS
When AUX2BOOSTVOL=000 this path is completely disconnected from the BOOST stage.
6
8
BIT
INPPGAMUTE
PGABOOST
LABEL
1
0
DEFAULT
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.
DESCRIPTION
PP, Rev 3.0, December 2008
Pre Production
18