PCM6260-Q1: Differential Gain adjust

Hi Xin,

Assuming you are using the EVM, what are your jumper settings and MICBIAS value at the input of the ADC? Also, the DC offset may not be a true +3.3V bias on both the positive and negative input depending on hardware setup coming from the APx5, so please measure the DC voltage with a multimeter on each input line and confirm.

In short, the DC bias, input configuration, or audio serial format can impact whether the device is recognizing a full scale 0dBFS signal, we can check these before any additional troubleshooting.

maybe you can check the schematic MICBIAS is 9V, as you supposed I calibration the input voltage to 3.3V, same as before

The connection to IN5P/M is fine and since it is AC coupled the DC offset does not have an impact that the IC can see.

Assuming TDM mode, try these settings on the AP.