K850
1203-2528 rev. 1
FUNCTIONAL OVERVIEW
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CODEC Block Schematic
CODEC CCO Voltage Source
There is an internal voltage source CCO that provides the necessary drive current for electret
microphones. The voltage source is I²C programmable to 2.2 V or 2.4 V. The source can be
disabled during standby. A typical use case with a microphone connected to MIC1 and the CCO
is shown in picture below.
Earphone Amplifier
The earphone amplifiers (BEARP and BEARN) are mainly intended to be differentially configured
and drive a low impedance dynamic transducer (earpiece) but they can also be single ended
configured. The BEARP and BEARN amplifiers can be powered down by the I2C. The amplifiers
can exhibit high impedance to 1.4 V or low impedance to ground when powered-down. Fifty-
one gains are available for BEARP and BEARN: from +15 dB down to –60 dB in 1.5 dB steps.
When the BEARP and BEARN outputs are operating in differential mode, an I²C selectable bit
must invert one of the inputs.
Technical Description
SEMC Troubleshooting Manual
65
(101)