Table 3-1. Voltage Regulators - Motorola P100 Series Detailed Service Manual

3-2
The following regulators are used:
Reference No.
U505
U506
U507
The 5 V source from U505 is applied to:
• RX back end circuitry
• RX/TX audio filters
• 1/2 VCC generator
• VCO power source (Q705, Q706)
• RX B+ (Q304)
• TXVB (Q407)
• VCTCXO
The 5 V source is also applied to transistor switches Q304 and Q407. Q304 is turned on by Q305
when RX_EN (from U101 Pin 71) is high, and supplies the source to mixer, IF IC and LNA. Q407 is
turned on by Q408 when TX_EN2 (from U101 Pin 85) is high, and supplies the "TXVB" source to the
first transmitter stage Q401 base, Q402 gate, APC power source (U401 Pin 8) and ANT switch
(CR401).
The 3.3 V regulated source from U506 is applied to:
• MCU IC U101
• EEProm IC U104
• DTMF IC U103
• Audio processor IC U102
• Microphone bias circuitry
• And applied to Key PCB (LCD driver power source)
The 10 V source from U507 is applied to Charge Pump.
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DC Power Distribution: DC Regulation and Distribution

Table 3-1. Voltage Regulators

Description
5V regulator
3.3V regulator
Voltage Doubler (10V)
Type
TK11250
TK11233
TC12140