wm8976gefl-v Wolfson Microelectronics plc, wm8976gefl-v Datasheet - Page 28

• Manufacturer Part Number: wm8976gefl-v
• Description: Stereo Codec With Speaker Driver
• Manufacturer: Wolfson Microelectronics plc

WM8976
ANALOGUE TO DIGITAL CONVERTER (ADC)
Figure 17 ADC Digital Filter Path
w
Figure 16 Microphone Bias Schematic
ADC DIGITAL FILTERS
Table 12 ADC Enable Control
The WM8976 uses a multi-bit, oversampled sigma-delta ADC. The use of multi-bit feedback and high
oversampling rates reduces the effects of jitter and high frequency noise. The ADC Full Scale input
level is proportional to AVDD. With a 3.3V supply voltage, the full scale level is 1.0V
greater than full scale may overload the ADC and cause distortion.
The ADC filters perform true 24 bit signal processing to convert the raw multi-bit oversampled data
from the ADC to the correct sampling frequency to be output on the digital audio interface. The digital
filter path for each ADC channel is illustrated in Figure 17.
The ADC is enabled by the ADCENL/R register bit.
R2
Power
management 2
REGISTER
ADDRESS
VMI
0
BIT
ADCENL
LABEL
internal
resistor
internal
resistor
0
DEFAULT
AGND
Enable ADC:
0 = ADC disabled
1 = ADC enabled
M
DESCRIPTION
MBVSEL=0
MICBIAS
= 1.8 x VMID
= 0.9 x AVDD
MBVSEL=1
MICBIAS
= 1.3 x VMID
= 0.65 x AVDD
PD Rev 4.4 July 2009
Production Data
rms
. Any voltage
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