WM8900LGEFK/RV Wolfson Microelectronics, WM8900LGEFK/RV Datasheet - Page 36

• 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
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Table 14 Input PGA Volume Control
See "Volume Updates" for more information on volume update bits, zero cross and timeout
operation.
See “Headphone Jack Detect” for more information on jack detect / debounce.
INPUT BOOST VOLUME CONTROL
The input path to the ADCs is via a boost stage, which mixes the signals from the microphone
input PGAs and from the line inputs.
The boost stage can apply up to +29dB gain to the microphone input PGA path, providing a total
maximum available analogue gain of +48dB from microphone to ADC input. The microphone PGA
path to the boost mixer may be muted using INL_MUTE and INR_MUTE as described in Table 14.
The Microphone PGA to boost gain settings are shown in Table 15. It is recommended that
maximum gain is applied to the input signals at the input PGA stage, with minimal boost gain being
applied where necessary. This prevents unnecessary amplification of small DC offsets from the
input PGA output.
R22 (16h)
Left Input
Volume
R23 (17h)
Right Input
Volume
REGISTER
ADDRESS
4:0
4:0
BIT
8
7
6
8
7
6
IN_VU
INL_ZC
INL_MUTE
INL_VOL
[4:0]
IN_VU
INR_ZC
INR_MUTE
INR_VOL
[4:0]
LABEL
0
0
1
01100
(0dB)
0
0
1
01100
(0dB)
DEFAULT
Input PGA Volume Update
Writing a 1 to this bit will cause left and
right Input PGA volume to be updated
simultaneously
Left Input PGA Zero Cross Detector
1 = Change gain on zero cross only
0 = Change gain immediately
Left Input PGA Analogue Mute
1 = Enable Mute
0 = Disable Mute
Note: IN_VU must be set to un-mute.
Left Input PGA Volume Control
11111 = +19dB
11110 = +18dB
. . 1dB steps down to
00000 = -12dB
Input PGA Volume Update
Writing a 1 to this bit will cause left and
right Input PGA volume to be updated
simultaneously
Right Input PGA Zero Cross Detector
1 = Change gain on zero cross only
0 = Change gain immediately
Right Input PGA Analogue Mute
1 = Enable Mute
0 = Disable Mute
Note: IN_VU must be set to un-mute.
Right Input PGA Volume Control
11111 = +19dB
11110 = +18dB
. . 1dB steps down to
00000 = -12dB
PD, August 2008, Rev 4.0
DESCRIPTION
Production Data
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