wm8941 Wolfson Microelectronics plc, wm8941 Datasheet - Page 21

• Manufacturer Part Number: wm8941
• Description: Mono Codec With Speaker Driver And Video Buffer
• Manufacturer: Wolfson Microelectronics plc

Production Data
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AUXILLIARY INPUT
Figure 7 Auxiliary Input Circuit
Table 5 Auxiliary Input Buffer Control
An auxiliary input circuit (Figure 7) is provided which consists of an amplifier which can be configured
either as an inverting buffer for a single input signal or as a mixer/summer for multiple inputs with the
use of external resistors. The circuit is enabled by the register bit AUXEN.
The AUXMODE register bit controls the auxiliary input mode of operation:
In buffer mode (AUXMODE=0) the switch labelled AUXSW in Figure 7 is open and the signal at the
AUX pin will be buffered and inverted through the aux circuit using only the internal components.
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.
R1
Power
management 1
R44
Input control
REGISTER
ADDRESS
6
3
BIT
AUXEN
AUXMODE
LABEL
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)
DESCRIPTION
PD, Rev 4.0, August 2008
WM8941
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