Hi All,
the analog input pins on the TLV320AIC3101 have be ac-coupled to analog input sources(four input single-end sources):
MIC2R/LINE2R, MIC2L/LINE2L/MICDET
MIC1RP/LINE1RP, MIC1LP/LINE1LP
I have mute all audio input(all audio input is not connected to ADC PGA) but still could hear slight audio output from the aic3101 output when PGA gain and audio input level is high...(mute uncompletely)
Per datasheet INPUT IMPEDANCE AND VCM CONTROL paragraph,
the input impedance will be Hi-Z when all audio input is not connected to ADC PGA, except..
that the pins on the device do include protection diode circuits connected to AVDD and AVSS. Thus, if any voltage is driven onto a pin approximately one diode drop (~0.6 V) above AVDD or one diode drop below AVSS, these protection diodes begin conducting current, resulting in an effective impedance that no longer appears as a high-impedance state.
Is it cause the mute uncompletely issue?
If yes, how could I avoid ? I have tried to modify Reg 20 and Reg 23 to keep unselected analog inputs is to weakly hold them at the common-mode input voltage of the ADC PGA. But it seems useless.
Thank you!!
