Microphone connection to ADAU1401A

Hello TomY.

You are correct that the power to the microphone would have to be supplied in another way since the 1401A does not have a micbias generator. The interesting thing about the 1401A is that the ADC is a current input ADC. So you can scale the full-scale voltage to make it more sensitive. If the microphone is able to drive the input impedance with enough level then you may be able to use it without an actual mic preamp. However, I feel that performance may suffer. The best way to know this is to obtain an evaluation board and a microphone that you would like to use and see if it is possible. See how it performs.

I do think the best method will be to have a preamp before the 1401A.

We have not tried to do this here in our labs. Perhaps someone else on the forum has attempted this? (Please respond if you have)

If this is a large project for a tier-1 customer then contact me directly to discuss.

Thanks,

Dave T

Hi, Dave T

Thank you for your comment.

>The interesting thing about the 1401A is that the ADC is a current input ADC.

Based on your this comment, I see the following spec from Datasheet.

And then, the spec of Microphone which I am considering to use is Input Voltage:2.5Vrms (max), Input Impedance:20kohm (min).

I = 2.5Vrms / 20kohm = 125uA

Is it possible to connect this Microphone to ADAU1401A directly?
How do you think?
If you can advice for me, it will be helpful.

Best regerds, TomY

Hi, Dave T

Do you have any advice?

Is it better to evaluate using actual microphone and Evaluation Board of ADAU1401A, after all?

Best regards, TomY