Using the AT89RFD-08 Board
AT89RFD-08 Hardware User Guide
2-29
4382E–MP3–05/06
The high frequency cut-off is essentially determined by the DAC digital filter response
(and hence its clock frequency). This frequency is 0.4535.Fs, Fs the sampling frequency
(i.e. 44.1KHz).
20. Confirm the isolation between L-channel and R-channel of headset line.
The specification is 80dB @1KHz. Note it is very sensitive to the environment (PCB).
Please use ground planes; capacitive coupling between the two outputs has to be
reduced to its minimum.