WM8903 Datasheet, PDF (33/178 Pages) Wolfson Microelectronics plc – Ultra Low Power CODEC for Portable Audio Applications

Production Data
WM8903
SINGLE-ENDED INPUT
The Single-Ended PGA configuration is illustrated in Figure 23 for the Left channel. The available
gain in this mode is from -1.55dB to +28.5dB in non-linear steps. The input impedance is 12k. The
input to the ADC is phase inverted with respect to the selected input pin. Different input pins can be
selected in the same mode by altering the L_IP_SEL_N field.
The equivalent configuration is also available on the Right channel; this can be selected
independently of the Left channel mode.
BYPASSL
IN1L
IN2L
IN3L
M
U
X
L_IP_SEL_N
-1.55dB to +28.5dB,
non-linear steps
-
+
VMID
INL_ENA
LIN_MUTE
LIN_VOL
ADC L
Single-Ended (inverting) Mode (L_MODE = 00)
Figure 23 Single Ended Mode
DIFFERENTIAL LINE INPUT
The Differential Line PGA configuration is illustrated in Figure 24 for the Left channel. The available
gain in this mode is from -1.55dB to +28.5dB in non-linear steps. The input impedance is 12k. The
input to the ADC is in phase with the input pin selected by L_IP_SEL_P. The input to the ADC is
phase inverted with respect to the input pin selected by L_IP_SEL_N.
As an option, common mode noise rejection can be provided in this PGA configuration, as illustrated
in Figure 24. This is enabled using the register bits defined in Table 5.
The equivalent configuration is also available on the Right channel; this can be selected
independently of the Left channel mode.
BYPASSL
IN1L
IN2L
IN3L
M
U
X
L_IP_SEL_N
M
U
X
-1.55dB to +28.5dB,
non-linear steps
-
+
+
-
INL_ENA
LIN_MUTE
LIN_VOL
INL_CM_ENA
ADC L
L_IP_SEL_P
Differential Line Mode (L_MODE = 01)
Figure 24 Differential Line Mode
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PD, Rev 4.5, June 2012
33