I am using the TPA3221 on a 2 sided PCB with a layout similar to the Evaluation board and following all the recommendations in the application note. It is set up in the 30dB gain mode as a master in a stereo BTL . .configuration in AD mode. Power supply voltage is 27 volts. VDD, AVDD, and GVDD are supplied by an external 5V supply.
Using a 100 Hz sine as input, the output shows a slight non-linearity fixed at the +/- 1 volt level . It is audible, around 1% distortion. It is independent of load. The power supply voltage has an effect, but the magnitude does not change significantly from 12 to 28 volts.
This non-linearity repeats around +/- 6 volts but is a smaller proportion of the waveform at that level.
Any thoughts would be appreciated.
