WM8985_07 WOLFSON [Wolfson Microelectronics plc], WM8985_07 Datasheet - Page 38

• Manufacturer Part Number: WM8985_07
• Description: Multimedia CODEC With Class D Headphone and Line Out
• Manufacturer: WOLFSON [Wolfson Microelectronics plc]

WM8985
ANALOGUE TO DIGITAL CONVERTER (ADC)
Figure 19 ADC Digital Filter Path
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Figure 18 Microphone Bias Schematic
ADC DIGITAL FILTERS
Table 13 ADC Enable Control
The WM8985 uses stereo multi-bit, oversampled sigma-delta ADCs. 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 AVDD1. With a 3.3V supply voltage, the full scale level is 1.0V
Any voltage 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 19.
The ADCs are enabled by the ADCENL/R register bit.
R2 (02h)
Power
management 2
REGISTER
ADDRESS
0
1
BIT
ADCENL
ADCENR
LABEL
0
0
DEFAULT
Enable ADC left channel:
0 = ADC disabled
1 = ADC enabled
Enable ADC right channel:
0 = ADC disabled
1 = ADC enabled
DESCRIPTION
PP, Rev 3.5, March 2007
Pre-Production
rms
38
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