Microphone - Panasonic EB-X300 Service Manual

In base-band power management, ADI U201 is designed for all base-band main power supply.
It provides seven regulator outputs for VCORE (1.8V), VMEM (2.93V), VEXT (2.93V), VRTC (1.8V), VCTCXO (2.75V),
VSIM (2.85V), VMIC (2.75V). VCORE and VMEM provide all digital power and VMEM provides all analogue power.
VRTC is used to charge Li-Mn coin cell for real time clock, and VCTCXO is the power source of 13MHz clock buffer.
U101 also provides the charge pump and hardware reset.

5.3.2. Microphone

The microphone is a noise cancelling type to provide improved speech pick-up, noise immunity and reduced echo. The GSM
standard requires that when in handheld mode, the transmitter audio frequency response must fit within the mask shown below:
5
(dB)
0
-5
-10
-15
100
Figure 5.11. Handheld GSM Transmit Audio Frequency Response Mask
Light
Controllers
Ram
GMSK
Filter
Filter
Filter
Filter
Battery
Charger
VCORE: 1.8 V, 80 mA
VMEM: 1.8 V or 2.8 V, 150 mA
VEXT: 2.8 V, 170 mA
VSIM: 1.8 V or 2.85 V, 20 mA
VRTC: 1.8 V, 200 µA
Figure 5.10. U201 Functional Block Diagram
ADC
DAC
DAC
DAC
DAC
ADC
ADC
Tone
DAC
ADC Mic
8 Voltage Regulators
1,000
Frequency (Hz)
– 5-11 –
LEDs
Crystal &
Varactor
Headphones or Headset
VABB
VMIC: 2.5 V, 1 mA
VVCXO: 2.75 V, 10 mA
10,000