WM8903LGEFK/RV Wolfson Microelectronics, WM8903LGEFK/RV Datasheet - Page 29

• 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
w
DIFFERENTIAL MICROPHONE INPUT
The Differential Mic PGA configuration is illustrated in Figure 25 for the Left channel. The available
gain in this mode is from +12dB to +30dB in 3dB linear steps. The input impedance is 120kΩ. In this
mode, there is no phase inversion between the input to the ADC and the input pin selected by
L_IP_SEL_N. The second (inverting) input pin is selected by L_IP_SEL_P in this mode.
The equivalent configuration is also available on the Right channel; this can be selected
independently of the Left channel mode.
Figure 25 Differential Mic Mode (Non-Inverting)
INPUT PGA GAIN CONTROL
The volume control gain for the Left and Right channels be independently controlled using the
LIN_VOL and RIN_VOL register fields as described in Table 3. The available gain range varies
according to the selected PGA Mode as detailed in Table 4. Note that the value ‘00000’ must not be
used in Differential Mic Mode, as the PGA will not function correctly under this setting. In single-
ended mode (L_MODE / R_MODE = 00b), the conversion from single-ended to differential within the
WM8903 adds a further 6dB of gain to the signal path.
Each input channel can be independently muted using LINMUTE and RINMUTE.
There is no feature to ensure that volume changes are implemented glitch-free. Therefore, it is
recommended to not adjust the gain dynamically whilst the signal path is enabled; the signal should
be muted at the input or output stage prior to adjusting the volume control.
Table 3 Input PGA Volume Control
R44 (2Ch)
Analogue Left
Input 0
R45 (2Dh)
Analogue
Right Input 0
REGISTER
ADDRESS
IN1L
IN2L
IN3L
BIT
4:0
4:0
7
7
LINMUTE
LIN_VOL [4:0]
RINMUTE
RIN_VOL [4:0]
MUX
MUX
LABEL
L_MODE = 1X
L_IP_SEL_P = 01
L_MODE = 1X
L_IP_SEL_N = 00
LIN_VOL
(+12dB to +30dB, in3dB steps)
LIN_VOL
(+12dB to +30dB, in3dB steps)
+
+
-
-
DEFAULT
00101
00101
1
1
Left Input PGA Mute
0 = not muted
1 = muted
Left Input PGA Volume
(See Table 4 for volume range)
Right Input PGA Mute
0 = not muted
1 = muted
Right Input PGA Volume
(See Table 4 for volume range)
PP, Rev 3.1, August 2009
DESCRIPTION
+
-
ADC L
BYPASSL
WM8903
29