Production Data
WM8776
It is recommended that a low pass filter be applied to the output from the DAC for hi-fi applications.
Typically a second order filter is suitable and provides sufficient attenuation of high frequency
components (the unique low order, high bit count multi-bit sigma delta DAC structure used in
WM8776 produces much less high frequency output noise). This filter is typically also used to
provide the 2x gain needed to provide the standard 2Vrms output level from most consumer
equipment. Figure 44 shows a suitable post DAC filter circuit, with 2x gain. Alternative inverting filter
architectures might also be used with as good results.
4.7k
Ω
4.7kΩ
+VS
_
51
Ω
10uF
1.8kΩ
7.5KΩ
+
+
-VS
1.0nF
680pF
10kΩ
Figure 44 Recommended Post DAC Filter Circuit
PD Rev 4.0 April 2005
55
w
WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
