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ADAU1761: Ground connection of earphone and microphone

Question asked by JoaJun-Kim on Nov 20, 2013
Latest reply on Dec 3, 2013 by KJBob



We are developing and manufacturing sound amplifier using ADAU1761.

We finished all designs and tests, then just start mass production.

There is a key problem at this time.


Our device has one microphone input + two earphone(stereo).

Microphone needs two lines(input(In+bias) & ground)

Earphone needs three lines(right & left & monoout pin)

Therefore, it needs 5 lines for earphone with microphone.


But it is not easy to find 5 pole phone jack and plug. (only order-base production, and no ready-made parts)

We tried to connect the microphone bias - earphone monoout, ground etc.

But the result was heavy noise, not satisfactory.


My question is "Are there any method which can use one microphone and two earphone(stereo) with 4 lines?"


Please, give me some advices for me.


Thanks very much.