LG CG225 - Cell Phone User manual

Date: March, 2006 / Issue 1.0
Service Manual Model : CG225
Service Manual
CG225_LG225

The information in this manual is subject to change without notice and should not be construed as a
commitment by LGE Inc. Furthermore, LGE Inc. reserves the right, without notice, to make changes to
equipment design as advances in engineering and manufacturing methods warrant.
This manual provides the information necessary to install, program, operate and maintain the CG225.
REVISED HISTORY
DATE ISSUE CONTENTS OF CHANGES S/W VERSION

- 2 -

- 3 -
1. Introduction ..................................... 5
1.1 Purpose................................................... 5
1.2 Regulatory Information............................ 5
1.3 Abbreviations .......................................... 7
2. General Performance...................... 9
2.1 Product Name ......................................... 9
2.2 Supporting Standard ............................... 9
2.3 Main Parts: GSM Solution........................9
2.4 H/W Features.........................................10
2.5 S/W Features .........................................12
3. H/W Circuit Description................ 14
3.1 RF Transceiver General Description..... 14
3.2 Receiver Part ........................................ 14
3.3 Transmitter Part .................................... 17
3.4 Digital Baseband (DBB) Processor........20
3.5 Analog Baseband (ABB) Processor...... 25
4. TROUBLE SHOOTING .................. 46
4.1 Main Components Placement............... 46
4.2 FPCB Components Placement ............. 47
4.3 Baseband Components ........................ 47
4.4 Main Components (Description) ........... 48
4.5 Power On Trouble................................. 49
4.6 Charging Trouble .................................. 50
4.7 LCD Display Trouble............................. 52
4.8 Camera Trouble .................................... 54
4.9 Receiver Trouble................................... 56
4.10 Microphone Trouble ............................ 60
4.11 Vibrator Trouble .................................. 63
4.12 Keypad Backlight Trouble ................... 65
4.13 Folder ON/OFF Trouble ...................... 67
4.14 SIM Detect Trouble ............................. 69
4.15 Earphone Trouble ............................... 71
4.16 RF Rx pass Trouble Shooting..............75
4.17 RF Tx pass Trouble Shooting ..............82
5. DOWNLOAD .................................. 90
5.1 Download Setup.................................... 90
5.2 Download Procedure ............................ 91
6. SERVICE AND CALIBRATION...... 98
6.1 Service S/W ...........................................98
7. CIRCUIT DIAGRAM ..................... 101
8. PCB LAYOUT............................... 107
9. ENGINEERING MODE .................... 111
10. STANDALONE TEST .................... 112
10.1 Setting Method ............................... 112
11. EXPLODED VIEW &
REPLACEMENT PART LIST...... 113
12.1 EXPLODED VIEW ............................ 113
12.2 Replacement Parts
<Mechanic component>.................... 115
<Main component> ........................... 118
12.3 Accessory ......................................... 131
Table of Contents

1. Introduction
- 5 -
1.1 Purpose
This manual provides the information necessary to repair, calibration, description and download the
features of the CG225
1.2 Regulatory Information
A. Security
Toll fraud, the unauthorized use of telecommunications system by an unauthorized part (for example,
persons other than your company’s employees, agents, subcontractors, or person working on your
company’s behalf) can result in substantial additional charges you’re your telecommunications
services. System users are responsible for the security of own system. There are may be risks of toll
fraud associated with your telecommunications system. System users are responsible for
programming and configuring the equipment to prevent unauthorized use. LGE does not warrant that
this product is immune from the above case but will prevent unauthorized use of common-carrier
telecommunication service of facilities accessed through or connected to it. LGE will not be
responsible for any charges that result from such unauthorized use.
B. Incidence of Harm
If a telephone company determines that the equipment provided to customer is faulty and possibly
causing harm or interruption in service to the telephone network, it should disconnect telephone
service until repair can be done. A telephone company may temporarily disconnect service as long as
repair is not done.
C. Changes in Service
A local telephone company may make changes in its communications facilities or procedure. If these
changes could reasonably be expected to affect the use of the CG225 or compatibility with the network,
the telephone company is required to give advanced written notice to the user, allowing the user to take
appropriate steps to maintain telephone service.
D. Maintenance Limitations
Maintenance limitations on the CG225 must be performed only by the LGE or its authorized agent.
The user may not make any changes and/or repairs expect as specifically noted in this manual.
Therefore, note that unauthorized alternations or repair may affect the regulatory status of the system
and may void any remaining warranty.
1. Introduction

1. Introduction
- 6 -
E. Notice of Radiated Emissions
The CG225 complies with rules regarding radiation and radio frequency emission as defined by local
regulatory agencies. In accordance with these agencies, you may be required to provide information
such as the following to the end user.
F. Pictures
The pictures in this manual are for illustrative purposes only; your actual hardware may look slightly
different.
G. Interference and Attenuation
An CG225 may interfere with sensitive laboratory equipment, medical equipment, etc. Interference
from unsuppressed engines or electric motors may cause problems.
H. Electrostatic Sensitive Devices
ATTENTION
Boards, which contain Electrostatic Sensitive Device (ESD), are indicated by the sign.
Following information is ESD handling:
•Service personnel should ground themselves by using a wrist strap when exchange system boards.
•When repairs are made to a system board, they should spread the floor with anti-static mat which is
also grounded.
•Use a suitable, grounded soldering iron.
•Keep sensitive parts in these protective packages until these are used.
•When returning system boards or parts like EEPROM to the factory, use the protective package as
described.

1. Introduction
- 7 -
1.3 Abbreviations
For the purposes of this manual, following abbreviations apply:
APC Automatic Power Control
BB Base Band
BER Bit Error Ratio
CC-CV Constant Current - Constant Voltage
DAC Digital to Analog Converter
DCS Digital Communication System
dBm dB relative to 1 milli watt
DSP Digital Signal Processing
EEPROM Electrical Erasable Programmable Read-Only Memory
EL Electroluminescence
ESD Electrostatic Discharge
FPCB Flexible Printed Circuit Board
GMSK Minimum Shift Keying
GPIB General Purpose Interface Bus
GSM Global System for Mobile Communications
IPUI International Portable User Identity
IF Intermediate Frequency
LCD Liquid Crystal Display
LDO Low Drop Output
LED Light Emitting Diode
OPLL Offset Phase Locked Loop
PAM Power Amplifier Module

1. Introduction
- 8 -
PCB Printed Circuit Board
PGA Programmable Gain Amplifier
PLL Phase Locked Loop
PSTN Public Switched Telephone Network
RF Radio Frequency
RLR Receiving Loudness Rating
RMS Root Mean Square
RTC Real Time Clock
FEM Front End Module
SIM Subscriber Identity Module
SLR Sending Loudness Rating
SRAM Static Random Access Memory
STMR Side Tone Masking Rating
TA Travel Adapter
TDD Time Division Duplex
TDMA Time Division Multiple Access
UART Universal Asynchronous Receiver/Transmitter
VCO Voltage Controlled Oscillator
VCTCXO Voltage Control Temperature Compensated Crystal Oscillator
WAP Wireless Application Protocol

2. General Performance
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2.1 Product Name
CG225 : Support GPRS (Class 10)
2.2 Supporting Standard
2.3 Main Parts: GSM Solution
2. General Performance
Item Feature Comment
GSM850/ E-GSM/DCS/PCS Quad Band
Supporting Standard Phase 2+
SIM Toolkit : Class 1,2,3
GSM-850 TX : 824 - 849 MHz
GSM-850 RX : 869 - 894 MHz
EGSM TX : 880 - 915 MHz
Frequency Range EGSM RX : 925 -960 MHz
DCS TX : 1710 - 1785 MHz
DCS RX : 1805 - 1880 MHz
PCS TX : 1850 - 1910 MHz
PCS RX : 1930 - 1990 MHz
WAP 2.0 : Yes
Application Standard MMS : Yes
JAVA : MIDP v2.0
CG225
Digital Baseband Calypso-AMR C035(D751992GHH))
Analog Baseband IOTA(TWL3025))
RF Chip Aero-2 (SI4210)

2. General Performance
- 10 -
2.4 H/W Features
Item Feature Comment
Form Factor Dual LCD Folder
Capacity Cell Size: Standard
Battery Standard: Li-Ion, 1000mAh(Min) 5.7(L)
x 34.15(W) x 53.55(H)mm
Packing Type: Inner Pack
Size Standard: 85.3 x 48 x 22.9 mm L x W x H
Weight 92.5g With Battery
PCB Main PCB : 8Layers, 1t
AVG TCVR Max : 290 mA (GSM, Power Level 5)
current (mA) Max : 120 mA (GSM, Power Level 19)
Standby Current 4 mA @ Paging Period 6
Standby time Up to 250 hours @ Paging Period 6
Charging time Below 3 hours @ Power Off /1000mAh
Talk time Min : 3hr 30 min @Power Level 7 @ 1000 mAh
Min : 6hr @Power Level 12
RX sensitivity GSM 850 : -105 dBm, EGSM : -105 dBm
DCS : -105 dBm, PCS : -105 dBm
TX output power GSM 850 : 32.0 dBm, EGSM : 32.0 dBm Class4 (GSM850, EGSM )
DCS : 30 dBm, PCS : 30 dBm Class1 (DCS, PCS)
GPRS compatibility GPRS Class 10
SIM card type Plug-In SIM 3V
-MAIN LCD : 65K Color CSTN (128*128)
Display -Sub : 96*64, Color Filter
-Backlight : White LED
Alphanumeric Key : 12 Function Key:
Function Key : 12 4 Key Navigation & OK,
Keypad Side Key : 3 F1, F2, SND, END/PWR,
Total Number of Keys : 27 Clear, Camera,Gallery

2. General Performance
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Item Feature Comment
Antenna External Type
Quad-band
System connector 24 Pin
Ear Phone Jack 3 Pole (φ2.5mm)
PC synchronization No CDROM
Memory Flash : 128Mbit / SRAM : 64Mbit AMD
Speech coding FR, EFR, HR, AMR
Data & Fax Built in Data & Fax support
Vibrator Built in Vibrator
MIDI 64 Poly Buzzer Function By Using
(for Buzzer Function) MIDI IC
Voice Recording No
Travel Adapter Yes
Ear-Microphone
Options Data Cable
Cigarette Lighter Adapter

2.5 S/W Features
2. General Performance
- 12 -
Item Feature Comment
RSSI 0~5 level
Battery Charging 0~4 level
Key Volume 0~5 level
Keypad Volume 0~5 level
Effect sound volume 0~5 level
Ring Volume 0~5 level
Time/Date Display Yes
Text Input T9
Multi-language Yes
Quick Access Mode Schedule/Ring Tone/Phonebook GPRS
PC Sync Schedule/Phonebook/SMS MS Scheduler & Outlook
Speed Dial Yes (2~9) Voice mail center →1 key
Profile Yes
CLIP/CLIR Yes
Phonebook 3 Number + 1 Memo + 1 e-mail Phone (Up to 255 entries)
Last Dial Number Yes (20)
Last Received Number Yes (20)
Last Missed Number Yes (10)
Search Number/Name Yes
Group 7 / User Editor
Fixed Dial Number Yes
Voice Memo 30 secs * 3
Call Remainder Yes
Network Selection Automatic / Manual

2. General Performance
- 13 -
Item Feature Comment
Mute Yes
Call Divert Yes
Call Barring Yes
Call Charge Yes
Call Duration Yes
SMS (EMS) 100
EMS Send/Receive/Save Yes Melody/Picture/Animation
MMS Yes
WAP Browser WAP 2.0
Java CLDC v1.0.3 / MIDP v1.0.3
Wall Paper Yes Max. 10 preset
Download Melody/ Over the WAP
Wallpaper (MMS)
Long Message Max. 918 Character(6page*153)
Cell Broadcast Yes
Calendar Yes
Memo 20
World Clock Yes
Unit Convert Length/Surface/Volume/Weight
Fax & Data Yes
SIM Lock Yes Operator Dependent
SIM Toolkit Class 1,2,3
Phone lock Yes
Security DRM (Forward-lock only)
CPHS Yes
IM Yes

3. H/W Circuit Description
- 14 -
3.1 RF Transceiver General Description
The RF parts consist of a transceiver part, a power amplifier part, a front-end module part, a voltage
supply part, and a VC-TCXO part.
The AeroII transceiver is composed of single RF chipset, Si4210-GM[U502] which is a quad-band
GSM/GPRS wireless communications.
This device integrated a receiver based on a low IF (200KHz) architecture and a transmitter based on
modulation loop architecture. The transceiver employed a 3 wire serial interface to allow an external
system controller to write the control registers for dividers, receive path gain, power down setting, and
other controls.
3.2 Receiver Part
The receiver part uses a low-IF receiver architecture that allows for the on-chip integration of the
channel selection filters, eliminating the external RF image reject filters and the IF SAW filter required
in conventional super-heterodyne architecture. The Si4210-GM[U502] integrates four differential input
LNAs that are matched to the 200 Ohm balanced-output SAW filters through external LC matching
networks.
A quadrature image-rejection mixer downconverts the RF signal to a 200kHz intermediate frequency
(IF) with the RFLO from the frequency synthesizer. The mixer output is amplified with an analog
programmable gain amplifier (PGA) and quadrature IF signal is digitized with high resolution A/D
converters (ADCs). The Si4210-GM[U502] downconverts the ADC output to baseband with a digital
200kHz quadrature LO signal. Digital decimation and IIR filters perform digital filtering , and remove
blocking and reference interference signals. After filtering, the digital output is scaled with digital PGA,
which is controlled with the DGAIN[5:0] bits in register 20h. The amplified digital output signal go
through with DACs that drive a differential analog signal onto the RXIP,RXIN,RXQP and RXQN pins to
interface to standard analog ADC input baseband ICs.
3. H/W Circuit Description
Table 3-1. Antenna Display
Antenna Bar Number Rx Power (dBm)
5 →4-85dBm±2dBm
4 →3-90dBm±2dBm
Antenna Display 3 →2-95dBm±2dBm
2 →1-100dBm±2dBm
1 →0-105dBm±2dBm

3. H/W Circuit Description
- 15 -
3.2.1. RF Front End
Digital Filter Digital Filter
RF front end consists of Front End Module(FL501), quad band LNAs integrated in transceiver(U502).
The Received RF signals (GSM-850 869MHz ~ 894MHz, EGSM 880 MHz ~ 960MHz, DCS 1710 MHz
~ 1880 MHz, PCS 1930MHz ~ 1990MHz) are fed into the antenna or mobile switch. An antenna
matching circuit is between the antenna and the mobile switch. The Front End Module(FL501) is used
for control the Rx and TX paths. And the input signals ANT_SW1 and ANT_SW2 of a FL501 are
directly connected to baseband controller to switch either TX or RX path on. Front End Module(FL501)
is an antenna switch module for Quad band phone. The logic and current is given below Table 3-2.
ADC
ADC
ADC
ADC
Digital Filter
Digital Filter
DAC
DAC
DAC
DAC
LOW
IF
LOW
IF
D
I
P
D
I
P
GSM
850
DCS
FL501
Front End Module
26MHz
I
Q
U502/Si4210
VCO + FREQUENCY
SYNTHESIZER
VCO + FREQUENCY
SYNTHESIZER
0/
90
0/
90
PGA PGA
X501
VC-TCXO
GSM
850
DCS
PCS
LNA
Baseband
(TI)
U102
(Calypso +)
+
U101
(IOTA)
Baseband
(TI)
U102
(Calypso +)
+
U101
(IOTA)
PCS
EGSM
EGSM
Figure 1. RF Receiver Block
Table 3-2. The Logic and Current
VC1(PIN 15) VC2(PIN 14) Current
GSM 850/EGSM RX 0 V 0 V < 0.1 mA
DCS/PCS RX 2.5~3.0 V 0 V < 0.1 mA
GSM-850/EGSM TX 0 V 2.5~3.0 V < 0.1 mA
DCS/PCS TX 2.5~3.0 V 2.5~3.0 V < 0.1 mA

3. H/W Circuit Description
- 16 -
3.2.2. Synthesizer
The Aero II transceiver integrates two complete PLLs including VCOs, varactors, resonators, loop
filters, reference and VCO dividers, and phase detectors. The RF PLL uses two multiplexed VCOs.
The RF1 VCO is used for receive mode, and the RF2 VCO is used for transmit mode. The IF PLL is
used only during transmit mode. All VCO tuning inductors are also integrated. The IF and RF output
frequencies are set by programming the N-Divider registers, NRF1, NRF2 and NIF. Programming the
N-Divider register for either RF1 or RF2 automatically selects the proper VCO.
Transmit modes should always use fφ= 200kHz. The IF and RF output frequencies are set by
programmi ng the N-Divider registers and also programmed via 3-wire interface with external system
controler.
Serial
I/O
Serial
I/O
Baseband
(TI)
U101
IOTA
+
U102
Calypso-
Baseband
(TI)
U101
IOTA
+
U102
Calypso-
U502/Si4210
RF1
RF2
PDIB
26MHz
X501
VC-TCXO
SCLK
SDIO
SEN
PDN
XTAL1
XOUT
XEN
Power
control
Power
control
Self
Tune
Self
Tune
1/N
1/N
1/N
1/N
DET
DET
Self
Tune
Self
Tune
DET
DET
To Rx/Tx
To Tx
RF PLL
IF PLL
PDRB
SDOSEL[4:0]
NIF[15:0]
NRF1[15:0]
NRF2[15:0]
1,2
1,2 65,130 65,130
÷
Figure 2. Synthesizer Block

3. H/W Circuit Description
- 17 -
3.3 Transmitter Part
The Transmitter part contains the transmitter parts of Si4210-GM[U502], Power Amp Module[U501]
and Front End Module[FL501]. The transmit section of Si4210-GM[U502] consists of an I/Q base band
up_converter, an offset phase-locked loop(OPLL) and two output buffers that can drive external power
amplifiers(PA). The RF GMSK outputs from the transmit VCO are fed directly to the RF power
amplifiers. The peak output power and the profile of the transmitted burst are controlled by means of
incorporated pow er control circuits inside of PA and DAC output from the Base band Controller. The
PA outputs pass to the antenna connector via Front End Module.

DET
DET
2
2
1
1
2
2
IF PLL
IF PLL
I
Q
Baseband
(TI)
U101
IOTA
+
U102
Calypso-
Baseband
(TI)
U101
IOTA
+
U102
Calypso-
PA_BAND
ANT_SW1,ANT_SW2
RFOG RFOD
GSM 850/
EGSM DCS/ PCS
RF PLL
RF PLL
D
I
P
D
I
P
DCS
FL501
Front End Module
PCS
GSM 850/
EGSM
Si4210 (U502)
PAM RF3166 (U501)
PA PA
Figure 3. RF Transmit Block

3. H/W Circuit Description
- 18 -
3.3.1. Power Amplifier
The RF3166 [U501] is a quad-band EGSM 900/GSM 850/DCS/PCS power amplifier module that
incorporat es an indirect closed loop method of power control. The indirect closed loop is fully self-
contained and it do es not require loop optimization. It can be driven directly from the DAC output in
the baseband circuit. On-board power control provides over 37 dB of control range with an analog
voltage input(Vramp). Efficien cy is 60% at GSM and 55% at DCS/PCS.
3.3.2. 26MHz Clock
The 26 MHz clock consists of a TCXO(Temperature Compensated Crystal Oscillator) which oscillates
at a frequency of 26 MHz. It is used within the Si4210 RF Main Chip, BB Analog chip-set(IOTA), Digita
l chip-set(Calypso-).
Figure 5. VC-TCXO Circuit
2GND
OUT 3
4
VCC
1VCONT
X501 26MHz
C528 1000p
1u
C530
R512
12K
1000p
C536
RF2.85V
TCXO_OUTAFC

3. H/W Circuit Description
- 19 -
3.3.3. Power Supplies and Control Signals
An external regulator(U503) is used to provide DC power to RF part. Every RF component except
power amp module uses this external regulator.
Figure 6 External regulator Circuit
3CE
GND
2
4
NC
VDD
1VOUT 5
RF2.85V
U503
R1114N281D-TR-F
VBAT
10u
C534
NA
C533
1000p
C560
1u
C535
C532
4.7u
RF_EN