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WM8775
APPLICATIONS INFORMATION
EXTERNAL CIRCUIT CONFIGURATION
In order to allow the use of 2V rms and larger inputs to the ADC 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 pulse. Figure 25 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
SOURCE
SELECTOR
5K
INPUTS
AINOPR
AINVGR
10uF 10K
AIN1R
10uF 10K
AIN2R
10uF 10K
AIN3R
10uF 10K
AIN4R
Figure 25 ADC Input Multiplexor Configuration
PP Rev 1.8, June 2004
33
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WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
