Power Supplies And Control Signals - LG -200 Service Manual

3. CPU Memories
Flash ROM
An 8Mbit programmable ROM is capable of being written while being still in circuit. Contains all the
main command software for the mobile.
SRAM
A 128Kbit by 8 temporary memory device, which is used by CPP-C for CPU execution.

2-6. Power Supplies and Control Signals

There are five regulators used in the phone: U24, U25, U26, U27 and U59. Those regulators are
dedicated power supplies, which provides most of the power requirements for the logic and RF circuits.
Each of these regulators can be controlled by individual enable signals. These are configured as the
following figure and table.
Regulator
Regulator 1
U24 VDD-CPP
Regulator 2
U25 VDD-SC1
Regulator 3
U26 VDD-RF
Regulator 4
U27 VDD-TXBUF
Regulator 5
U59 VDD-OSC
Voltage
2.85V ± 0.5
2.85 ± 0.5
2.85 ± 0.5
2.85 ± 1.5 Transmit power control
2.9 ± 0.04V
[Table - Power Supply]
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2. TECHNICAL BRIEF
Powers
CPP-2 digital
circuitry, LCD
SC1 digital circuitry
RF circuitry
VCO
Enable Signal
SHTDMN-B
SHTDMN-B
RF-REG-EN
RF-REG-EN
XOEN-SC1 OR
XOEN-CPP