ADAU1761 codec input & output specification

Hello Ranjini,

Ranjini said:
ADAU1761 codec datasheet says 0.92Vrms is the full-scale output at AVDD = 3.3V. 920mV will be at the differential pairs(LOUTP & LOUTN) or will it be divided? Is this max output voltage? Is the same applicable for LHP?

The line out N and P will give you 0.92Vrms between the two pins. So if you only look at one of them you will get half of that, 0.46Vrms.

The Headphone output has another amplifier internally to provide the headphone output so it will give you 0.92Vrms single ended. The datasheet numbers are correct. there are no errors there.

Ranjini said:
What is the minimum & maximum input this codec can handle?

Minimum would be the noise floor.

Are you asking for the absolute DC voltage at the pin without a coupling cap?

the input pins are riding on the common mode voltage which will be around 1.65Vdc (AVDD/2).

You can calculate this by using the peak to peak max input voltage of 2.83V.

2.83/2 = 1.415V

AVDD= 3.3V then the CM voltage will be 1.65V

1.65 + 1.415 = 3.065V

1.65 - 1.415 = 0.235V

Dave T

Ranjini said:
What is the minimum output of the codec?

I answered that above

Ranjini said:
Could you please share the waveform of the DAC output

I do not understand this seemingly simple question? It will be whatever waveform you put into the DAC's digital input is the simple answer.

Are you wondering if it is ground referenced? No, it is riding on the common mode voltage just like the input. So you need to use a coupling capacitor to block the DC.

For the "capless" headphone output you reference to the Mono output which will be at the common mode voltage. So do not take the headphone output and ground it externally. It is not referenced to ground, it is referenced to the common mode voltage using the Mono Output. This is all explained in the datasheet on page 36 for the Rev E datasheet. The Headphone Output section.