WM8900LGEFK/RV Wolfson Microelectronics, WM8900LGEFK/RV Datasheet - Page 48

• Manufacturer Part Number: WM8900LGEFK/RV
• Description: Audio CODECs Ultra Low Power Hi-Fi CODEC
• Manufacturer: Wolfson Microelectronics

Specifications of WM8900LGEFK/RV

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

WM8900
OUTPUT SIGNAL PATH
w
DAC sample rates. See "Digital Filter Characteristics" section for details of DAC filter
characteristics.
Table 33 DAC Sloping Stopband Filter
DAC SIGMA-DELTA CLOCK RATE
When operating the DAC at lower sample rates (e.g. during voice communication) it is
recommended
(DAC_SDMCLK_RATE = 1) to maintain an independent clock rate and reduce idle channel noise.
Setting DAC_SDMCLK_RATE to 0 will allow the DAC clock to scale with sample rate and give a
minimal power consumption improvement, at the expense of idle channel noise increasing
Table 34 DAC Sigma-delta Modulator Clock Rate
The WM8900 has two analogue output mixers which allow the ADC bypass, DAC output and
LINPUT3 (RINPUT3) and AUX signals to be combined as desired. The flexible configuration of
these mixers allows a mono mix to be generated as well as combining audio signals (eg. speech)
from the input bypass path. The output mixers are connected to two stereo line outputs; the built-in
ground-referenced headphone driver may be connected to one of these line output pairs.
OUTPUT MIXER ENABLE
The output mixers are independently enabled by the MIXOUTL_ENA and MIXOUTR_ENA register
bits, as described in Table 35.
The output mixers bias current can be optimised by the MIXOUT_BIAS register bits. Note that the
optimum setting for minimum power consumption is not the power-on default value.
Table 35 Output Mixers Enable
R10 (0Ah)
DAC Control
R10 (0Ah)
DAC Control
R3 (03h)
Power
Management
3
R115 (R73h)
Output Bias
Control
REGISTER
ADDRESS
REGISTER
ADDRESS
REGISTER
ADDRESS
that
12
BIT
8:7
BIT
BIT
3
2
8
the
DAC_SDMCLK_RATE
DAC_SB_FILT
DAC
MIXOUTL_ENA
MIXOUTR_ENA
MIXOUT_BIAS
LABEL
LABEL
LABEL
sigma-delta
0
DEFAULT
modulator
1
DEFAULT
DEFAULT
00
0
0
Selects DAC filter characteristics
0 = Normal mode
1 = Sloping stopband mode
clock
DAC sigma delta modulator clock
0 = DAC clock scales with sample
rate
1 = DAC clock independent of
sample rate
Left output mixer enable
0 = Mixer disabled
1 = Mixer enabled
Right output mixer enable
0 = Mixer disabled
1 = Mixer enabled
Adjusts output mixer bias
00 = Full bias
01 = Half bias (recommended)
10 = Reserved
11 = Reserved
PD, August 2008, Rev 4.0
is
DESCRIPTION
DESCRIPTION
enabled
DESCRIPTION
Production Data
by
default
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