WM8903LGEFK/RV Wolfson Microelectronics, WM8903LGEFK/RV Datasheet - Page 61

• Manufacturer Part Number: WM8903LGEFK/RV
• Description: Audio CODECs ULTRA LOW PWR HI FI CODEC
• Manufacturer: Wolfson Microelectronics

Specifications of WM8903LGEFK/RV

• Audio Codec Type: Stereo Codec
• No. Of Adcs: 2
• No. Of Dacs: 2
• No. Of Input Channels: 6
• No. Of Output Channels: 8
• Adc / Dac Resolution: 24bit
• Sampling Rate: 96kHz
• Operating Temperature Range: -40°C To +85°C
• Rohs Compliant: Yes
• Adcs / Dacs Signal To Noise Ratio: 96dB
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Production Data
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DAC SLOPING STOPBAND FILTER
Two DAC filter types are available, selected by the register bit DAC_SB_FILT. When operating at
sample rates <= 24kHz (e.g. during voice communication) it is recommended that the sloping
stopband filter type is selected (DAC_SB_FILT=1) to reduce out-of-band noise which can be audible
at low DAC sample rates. See “Digital Filter Characteristics” for details of DAC filter characteristics.
Table 35 DAC Sloping Stopband Filter
DAC BIAS CONTROL
The analogue circuits within the DAC use the Master bias current (see “Reference Voltages and
Master Bias”). The DAC bias currents can also be reduced using the DACBIAS_SEL and
DACVMID_SEL fields as described in Table 36. These can be used to reduce power consumption,
but may have a marginal impact on audio performance in some usage modes.
The DAC bias currents can be increased using the DAC_BIAS_BOOST field. Setting this bit doubles
the bias level of DACBIAS_SEL and DACVMID_BIAS_SEL. This offers a performance improvement,
but also an increase in power consumption.
Note that the increased DAC VMID buffer bias is unlikely to give better performance; when
DAC_BIAS_BOOST is set, it is recommended to set DACVMID_BIAS_SEL = 01 in order to restore
the Normal DAC VMID buffer bias level.
Table 36 DAC Bias Control
R33 (21h)
DAC Digital 1
R8 (08h)
Analogue
DAC 0
REGISTER
ADDRESS
REGISTER
ADDRESS
4:3
2:1
BIT
5
BIT
11
DAC_BIAS_BOO
ST
DACBIAS_SEL
DACVMID_BIAS_
SEL
DAC_SB_FILT
LABEL
LABEL
DEFAULT
DEFAULT
00
00
0
0
DAC Bias boost
0 = Disable
1 = Enable
When DAC Bias boost is enabled, the
bias selected by DACBIAS_SEL and
DACVMID_BIAS_SEL are both
doubled.
DAC bias current select
00 = Normal bias
01 = Normal bias x 0.5
10 = Normal bias x 0.66
11 = Normal bias x 0.75
DAC VMID buffer bias select
00 = Normal bias
01 = Normal bias x 0.5
10 = Normal bias x 0.66
11 = Normal bias x 0.75
Selects DAC filter characteristics
0 = Normal mode
1 = Sloping stopband mode
(recommended when fs <= 24kHz)
PD, Rev 4.0, September 2010
DESCRIPTION
DESCRIPTION
WM8903
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