WM8750JL Datasheet, PDF (51/61 Pages) Wolfson Microelectronics plc – Stereo CODEC for Portable Audio Applications

Production Data
WM8750JL
DIGITAL FILTER CHARACTERISTICS
The ADC and DAC employ different digital filters. There are 4 types of digital filter, called Type 0, 1, 2
and 3. The performance of Types 0 and 1 is listed in the table below, the responses of all filters is
shown in the proceeding pages.
PARAMETER
TEST CONDITIONS
MIN
ADC Filter Type 0 (USB Mode, 250fs operation)
Passband
+/- 0.05dB
0
-6dB
Passband Ripple
Stopband
0.584fs
Stopband Attenuation
f > 0.584fs
-60
ADC Filter Type 1 (USB mode, 272fs or Normal mode operation)
Passband
+/- 0.05dB
0
-6dB
Passband Ripple
Stopband
0.5465fs
Stopband Attenuation
f > 0.5465fs
-60
High Pass Filter Corner
Frequency
-3dB
-0.5dB
-0.1dB
DAC Filter Type 0 (USB mode, 250fs operation)
Passband
+/- 0.03dB
0
-6dB
Passband Ripple
Stopband
0.584fs
Stopband Attenuation
f > 0.584fs
-50
DAC Filter Type 1 (USB mode, 272fs or Normal mode operation)
Passband
+/- 0.03dB
0
-6dB
Passband Ripple
Stopband
0.5465fs
Stopband Attenuation
f > 0.5465fs
-50
Table 46 Digital Filter Characteristics
TYP
0.5fs
0.5fs
3.7
10.4
21.6
0.5fs
0.5fs
MAX
0.416fs
+/- 0.05
0.4535fs
+/- 0.05
0.416fs
+/-0.03
0.4535fs
+/- 0.03
DAC FILTERS
Mode
Group Delay
0 (250 USB)
11/FS
1 (256/272)
16/FS
2 (250 USB, 96k mode)
4/FS
3 (256/272, 88.2/96k mode) 3/FS
Table 47 ADC/DAC Digital Filters Group Delay
ADC FILTERS
Mode
Group Delay
0 (250 USB)
13/FS
1 (256/272)
23/FS
2 (250 USB, 96k mode)
4/FS
3 (256/272, 88.2/96k mode) 5/FS
UNIT
dB
dB
dB
dB
Hz
dB
dB
dB
dB
TERMINOLOGY
1. Stop Band Attenuation (dB) – the degree to which the frequency spectrum is attenuated (outside audio band)
2. Pass-band Ripple – any variation of the frequency response in the pass-band region
w
PD, April 2012, Rev 4.1
51