WMOi3 integrated Modem
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10
3.2.4.2
Microphone 1
The MIC1 inputs are differential and do not include internal bias. To use these
inputs with an electret microphone, bias has to be generated outside the
WMOI3 modem according to the characteristic of this electret microphone.
These inputs are the standard ones used for an external headset or a handsfree
kit. The connection can be either differential or single-ended but using a
differential connection in order to reject common mode noise and TDMA noise
is recommended. When using a single-ended connection, be sure to have a
very good ground plane, a very good filtering as well as shielding in order to
avoid any disturbance on the audio path.
The gain of MIC1 inputs is internally adjusted. The gain can be tuned from
30dB to 51dB.
Pin description
Pin description
Pin description
Pin description
Signal
Signal
Signal
Signal
Pin #
Pin #
Pin #
Pin #
I/O
I/O
I/O
I/O
I/O type
I/O type
I/O type
I/O type
Description
Description
Description
Description
MIC1P
20
I
Analog
Microphone 1 positive
input
MIC1N
22
I
Analog
Microphone 1 negative
input
3.2.4.3
Speaker 2
Speaker outputs SPK2 are push-pull amplifiers and can be loaded down to 50
Ohms and up to 1nF. These outputs are differential and the output power can
be adjusted by step of 2dB. The output can be directly connected to a speaker.
The connection can be differential or single-ended but using a differential
connection to reject common mode noise and TDMA noise is recommended.
When using a single-ended connection, be sure to have a very good ground
plane, a very good filtering as well as shielding in order to avoid any
disturbance on the audio path.
Pin description
Pin description
Pin description
Pin description
Signal
Signal
Signal
Signal
Pin #
Pin #
Pin #
Pin #
I/O
I/O
I/O
I/O
I/O type
I/O type
I/O type
I/O type
Description
Description
Description
Description
SPK2P
10
O
Analog
Speaker 2 positive output
SPK2N
8
O
Analog
Speaker 2 negative output
