LG gd350 Service Manual page 57

3. TECHNICAL BRIEF
Microphone Supply
X-GOLD™213 has a single ended power-supply concept for electret microphones:
For both modes a minimal load capacitance of t.b.d. nF is necessary to guarantee stable operation of the
buffer.
The maximal load capacitance must not exceed t.b.d. nF.
2 microphone supplies VMIC and VUMIC are available. The supply VUMIC has a ultra-low-power mode,
where the current consumption is minimum, whilst at the same time the noise performance is reduced.
For this purpose the VUMIC is directly supplied out of the VMIC regulator, the Mic-Buffer can be switched
off and only the quiescent current of the VMIC regulator is present. This mode can be used to supply a
headset and allow accessory detection with highly reduced current consumption For normal operation
the supply can be switched to normal operation mode with improved noise performance. In case of an
digital microphone VMIC can be used for supplying this microphone.
Figure 3.12.5 Typical Microphone Supply Generation (alternative)
Figure 3.12.5 Typical Microphone Supply Generation (alternative)
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3. TECHNICAL BRIE
3. TECHNICAL BRIEF
Only for training and service purposes