Analog CoProcessor / Electret Microphone / Scan_ADC: where to connect VAGND?

[RaAl_264636]

Hi,

I want to connect a electret microphone, using the Scan_ADC component of the Analog CoProcessor.

   

I wonder where to connect the VAGND input signal of the Scan_ADC component when filtering on channel 0 is used? The VREF component seems to only support VDDA. Do I have to make an external connection to GND by a dedicated pin?

Regards,

Ralf

[Vasanth]

Hi,

You can use the pVref component, and  use a high pass filter biased at pVref voltage and input side too. The connection to resistor end can be given through an Opamp buffer.

Best Regards,
VSRS

[RaAl_264636]

Hi VSRS,

thank you for that tip. So, that means that there's (currently) no way to connect VAGND internally to the ADC?

Regards,

Ralf

[Vasanth · Accepted solution]

Hello Ralf,

You can use the pVref as the input to angd terminal of the ADC. As there is opamp buffer stage inside you can directly connect it. The connection I have specified was for the biasing of the signal with the same agnd.

Best Regards,
VSRS

[RaAl_264636]

Hi VSRS,

okay, will try that. I just wondered why there's no direct (A)GND connection possible.

Thanks a lot for your help.

Regards,

Ralf