Production Data
WM8776
APPLICATIONS INFORMATION
EXTERNAL CIRCUIT CONFIGURATION
In order to allow the use of 2V rms and larger inputs to the ADC and AUX inputs, a structure is used
that uses external resistors to drop these larger voltages. This also increases the robustness of the
circuit to external abuse such as ESD pulses. Figure 41 shows the ADC input multiplexor circuit with
external components allowing 2Vrms inputs to be applied.
5K
AINOPL
AINVGL
10uF 10K
AIN1L
10uF 10K
AIN2L
10uF 10K
AIN3L
10uF 10K
AIN4L
10uF 10K
AIN5L
5K
SOURCE
AINOPR
SELECTOR
INPUTS
AINVGR
AIN1R
10uF 10K
10uF 10K
10uF 10K
10uF 10K
10uF 10K
AIN2R
AIN3R
AIN4R
AIN5R
Figure 41 ADC Input Multiplexor Configuration
10K
MX[0]
MX[1]
MX[2]
DACL/R
10K
10K
10K
10uF
AUXL/R
AUX input
BYPASSL/R
Figure 42 5.1 Channel Input Multiplexor Configuration
PD Rev 4.0 April 2005
53
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WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
