WM8850
Pre-Production
The supported input configurations are described in Table 11 below:
BTL
DIFFERENTIAL
MODE
MODE
ACTIVE PINS
NOTES
0
X
Single Ended
VIN2LP
VIN2RP
Input impedance varies with
gain setting – minimum 10kΩ
Suitable for microphone or
line level signals
1
1
0
Differential
(Microphone)
VIN2LP
VIN2LN
VIN2RP
VIN2RN
Input impedance does not
vary with gain setting –
typically 120kΩ
Suitable for microphone (low-
level) signals only
1
Pseudo-Differential
VIN2LP
VIN2LN
VIN2RP
VIN2RN
Input impedance varies with
gain setting – minimum 10kΩ
Suitable for microphone or
line level signals
Table 11 Port-B Configuration Options
See Figure 8 for examples of the external connections required in each of the supported input
configurations.
Figure 8 Port-B Example External Connections (one channel shown)
A microphone pre-amplifier is available as part of the Port-B node. This amplifier can be used to
boost microphone inputs by +10dB, +20dB or +30dB. Alternatively, the gain of the pre-amplifier can
be set to 0dB. It is not possible to use different gain settings for the left and right channels, and the
pre-amplifier does not support mute. The microphone pre-amplfier is controlled by the Amplifier
Gain/Mute Verb.
PP, April 2011, Rev 3.2
44
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WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
