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WM8775

w

PP Rev 1.8, June 2004

33

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.

AIN1L

10K

10uF

AIN2L

10K

10uF

AIN3L

10K

10uF

AIN4L

10K

10uF

AIN1R

10K

10uF

AIN2R

10K

10uF

AIN3R

10K

10uF

AIN4R

10K

10uF

SOURCE

SELECTOR

INPUTS

AINVGR

AINOPR

5K

AINVGL

AINOPL

5K

Figure 25 ADC Input Multiplexor Configuration