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8.1.2.2 Cellular phone connector V100
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8.1.3 Operation
Operating voltage is fed to pin VBATT (V100.3). It is regulated to 3.3 V (VB) with
I101.
Reference voltage VB/2 is produced with voltagedivider R120 and R 121.
Bias voltage to microphone is fed through R100, R101 and R102.
Audiosignal from microphone is amplified and filtered by amplifiers I100A and I100B.
Audiosignal to earphone is amplified by amplifiers I100C and I100D.
Detection of headset adapter is done by pulling pin V100/15 (EXTIO) to ground with
resistor R151.
8EHD60GB.fm
NC
NC
VBATT
battery voltage
NC
EXTMIC
microphone signal
GND
ground
GND
ground
EXTERP
earphone signal
CADET
not used
NC
NC
NC
NC
NC
EXTIO
external I/O
NC
Product: EHD-60 (Headset) /
1.3.1999
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