Owner manual

DS837F2 29
CS4385A
4.10 Analog Output and Filtering
Cirrus Logic application note AN55, “Design Notes for a 2-Pole Filter with Differential Input,” discusses the
second-order Butterworth filter and differential-to-single-ended converter shown in Figure 23. The CS4385A
does not include phase or amplitude compensation for an external filter. Therefore, the DAC system phase
and amplitude response are dependent on the external analog circuitry. The off-chip filter has been de-
signed to attenuate the typical full-scale output level to below 2 Vrms.
Figure 22 shows how the full-scale differential analog output level specification is derived.
AOUT+
AOUT-
Full-Scale Output Level= (AOUT+) - (AOUT-)= 6.6 Vpp
4.15 V
2.5 V
0.85 V
4.15 V
2.5 V
0.85 V
Figure 22. Full-Scale Output
Figure 23. Recommended Output Filter