WM8903LGEFK/RV Wolfson Microelectronics, WM8903LGEFK/RV Datasheet - Page 49

• 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

Pre-Production
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DAC INTERFACE VOLUME BOOST
A digital gain function is available at the audio interface to boost the DAC volume when a small
signal is received on DACDAT. This is controlled using register bits DAC_BOOST[1:0]. To prevent
clipping at the DAC input, this function should not be used when the boosted DAC data is expected
to be greater than 0dBFS.
Table 23 Digital Mixing Control
DIGITAL SIDETONE
Digital sidetone mixing (from ADC output into DAC input) is available when ADCs and DACs are
operating at the same sample rate. Digital data from either left or right ADC can be mixed with the
audio interface data on the left and right DAC channels. Sidetone data is taken from the ADC
high-pass filter output, to reduce low frequency noise in the sidetone (e.g. wind noise or mechanical
vibration).
The digital sidetone will not function when ADCs and DACs are operating at different sample rates.
When using the digital sidetone, it is recommended that the ADCs are enabled before un-muting the
DACs to prevent pop noise. The DAC volumes and sidetone volumes should be set to an appropriate
level to avoid clipping at the DAC input.
When using the digital sidetone, it is recommended that dynamic control of the charge pump is not
enabled, i.e. CP_DYN_PWR should be cleared to 00. See the “Charge Pump” section for details.
The digital sidetone is controlled as shown in Table 24.
Table 24 Digital Sidetone Control
R24 (18h)
Audio
Interface 0
R32 (20h)
DAC Digital 0
REGISTER
REGISTER
ADDRESS
ADDRESS
10:9
11:8
BIT
BIT
7:4
3:2
1:0
DAC_BOOST
[1:0]
ADCL_DAC_SV
OL [3:0]
ADCR_DAC_SV
OL [3:0]
ADC_TO_DACL
[1:0]
ADC_TO_DACR
[1:0]
LABEL
LABEL
DEFAULT
DEFAULT
0000
0000
00
00
00
DAC Input Volume Boost
00 = 0dB
01 = +6dB (Input data must not
exceed -6dBFS)
10 = +12dB (Input data must not
exceed -12dBFS)
11 = +18dB (Input data must not
exceed -18dBFS)
Left Digital Sidetone Volume
(See Table 25 for volume range)
Right Digital Sidetone Volume
(See Table 25 for volume range)
Left DAC Digital Sidetone Source
00 = No sidetone
01 = Left ADC
10 = Right ADC
11 = Reserved
Right DAC Digital Sidetone Source
00 = No sidetone
01 = Left ADC
10 = Right ADC
11 = Reserved
PP, Rev 3.1, August 2009
DESCRIPTION
DESCRIPTION
WM8903
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