LG C3380 User manual

Service Manual Model : C3380
Date: November, 2005 / Issue 1.0
Service Manual
C3380

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1. INTRODUCTION .............................. 5
1.1 Purpose .................................................. 5
1.2 Regulatory Information............................ 5
1.3 Abbreviations .......................................... 7
2. PERFORMANCE.............................. 9
2.1 H/W Features.......................................... 9
2.2 Technical Specification ......................... 10
3. TECHNICAL BRIEF ...................... 16
3.1 Transceiver ........................................... 16
3.2 Power Amplifier Module ....................... 21
3.3 26 MHz Clock........................................ 22
3.4 Power Supplies for RF Circuits ............. 23
3.5 Digital Main Processor .......................... 24
3.6 Analog Main & Power Management
Processor.................................................. 30
3.7 Display and Interface ............................ 40
3.8 Camera Interface .................................. 42
3.9 Keypad Switches and Scanning ........... 44
3.10 Microphone ......................................... 45
3.11 Main Speaker...................................... 45
3.12 Headset Interface................................ 46
3.13 Key Back-light Illumination.................. 47
3.14 LCD Back-light Illumination................. 48
3.15 VIBRATOR.......................................... 49
3.16 BLUETOOTH .......................................50
4. TROUBLE SHOOTING ................. 52
4.1 RX Trouble............................................ 52
4.2 TX Trouble ............................................ 60
4.3 Power On Trouble................................. 68
4.4 Charging Trouble ...................................70
4.5 Vibrator Trouble .....................................72
4.6 LCD Trouble...........................................74
4.7 Camera Trouble .....................................76
4.8 Speaker Trouble ....................................78
4.9 SIM Card Interface Trouble....................80
4.10 Earphone Trouble ................................82
4.11 KEY backlight Trouble .........................84
4.12 Receiver Trouble .................................86
4.13 Microphone Trouble .............................88
4.14 RTC Trouble ........................................90
4.15 Indication LED Trouble ........................92
4.16 Folder on/off Trouble............................94
4.17 Bluetooth Trouble.................................96
5. DOWNLOAD AND CALIBRATION.. 100
5.1 Download ............................................ 100
5.2 Calibration............................................106
6. BLOCK DIAGRAM ...................... 109
7. CIRCUIT DIAGRAM ..................... 111
8. PCB LAYOUT ............................... 117
9. ENGINEERING MODE ..................119
9.1 BB Test [MENU 1]................................120
9.2 RF Test [MENU 2]................................122
9.3 MF mode [MENU 3] .............................122
9.4 Trace option [MENU 4] ........................123
9.5 Call timer [MENU 5] .............................123
9.6 Fact. Reset [MENU 6] ..........................123
9.7 S/W version..........................................123
10. STAND ALONE TEST .................124
10.1 Introduction ........................................124
10.2 Setting Method...................................124
10.3 Means of Test ....................................125
11. AUTO CALIBRATION..................127
11.1 Overview ............................................127
11.2 Requirements.....................................127
11.3 Menu and Settings .............................127
11.4 AGC ...................................................129
11.5 APC....................................................129
11.6 ADC ...................................................129
11.7 Setting................................................129
11.8 How to do calibration .........................129
12. EXPLODED VIEW &
REPLACEMENT PART LIST ..... 131
12.1 Exploded View .................................. 131
12.2 Replacement Parts ............................133
12.3 Accessory ......................................... 150
Table Of Contents

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1. INTRODUCTION
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1.1 Purpose
This manual provides the information necessary to repair, calibration, description and download the
features of this model.
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 for 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. The manufacturer 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.
The manufacturer 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 this phone 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 this model must be performed only by the manufacturer 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
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E. Notice of Radiated Emissions
This model 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
Phone 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
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1.3 Abbreviations
For the purposes of this manual, following abbreviations apply:
APC Automatic Power Control
BB Baseband
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
ESD Electrostatic Discharge
FPCB Flexible Printed Circuit Board
GMSK Gaussian 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

1. INTRODUCTION
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PAM Power Amplifier Module
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
SAW Surface Acoustic Wave
SIM Subscriber Identity Module
SLR Sending Loudness Rating
SRAM Static Random Access Memory
PSRAM Pseudo SRAM
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. PERFORMANCE
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2.1 H/W Features
2. PERFORMANCE
Item Feature Comment
Li-ion, 1000mAh
Standard Battery Battery Size : 34.15 (W) ×53.55(H) ×5.7(T) [mm]
Battery Weight : 25g
Under the minimum current consumption environment
Stand by Current (such as paging period 9), the level of standby current
is below 4mA.
Talk time Up to 3.5 hours (GSM TX Level 5)
Stand by time Up to 200 hours (Paging Period: 9, RSSI: -85 dBm)
Charging time Approx. Under 3.75 hours
RX Sensitivity GSM, EGSM: -107dBm, DCS: -107dBm
TX output power GSM, EGSM: 33dBm(Level 5),
DCS: 30dBm(Level 0)
GPRS compatibility Class 10
SIM card type 3V Small
Display Main LCD : CSTN 128 x 160 pixel 65K Color
Sub LCD : STN 96 x 64 pixel MONO Color
Hard icons. Key Pad
0 ~ 9, #, *, Up/Down Navigation Key
Status Indicator Menu Key, Clear Key
Send Key, END/PWR Key
Soft Key(Left/Right)
ANT Internal
EAR Phone Jack Yes (mono)
PC Synchronization Yes
Speech coding EFR/FR/HR
Data and Fax Yes
Vibrator Yes
Loud Speaker Yes
Voice Recoding Yes
Microphone Yes
Speaker/Receiver One way dual speaker
Travel Adapter Yes
MIDI 40 Poly (Mono SPK)
Options Data Kit , CD

2. PERFORMANCE
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2.2 Technical Specification
Item Description Specification
GSM
TX: 890 + n x 0.2 MHz
RX: 935 + n x 0.2 MHz (n=1~124)
EGSM
1Frequency Band TX: 890 + (n-1024) x 0.2 MHz
RX: 935 + (n-1024) x 0.2 MHz (n=975~1024)
DCS
TX: 1710 + (n-512) x 0.2 MHz
RX: 1805 + (n-512) x 0.2 MHz (n=512~885)
2Phase Error RMS < 5 degrees
Peak < 20 degrees
3Frequency Error < 0.1 ppm
GSM, EGSM
Level Power Toler. Level Power Toler.
533 dBm 2dB 13 17 dBm 3dB
631 dBm 3dB 14 15 dBm 3dB
729 dBm 3dB 15 13 dBm 3dB
827 dBm 3dB 16 11 dBm 5dB
925 dBm 3dB 17 9 dBm 5dB
10 23 dBm 3dB 18 7 dBm 5dB
11 21 dBm 3dB 19 5 dBm 5dB
4Power Level 12 19 dBm 3dB
DCS
Level Power Toler. Level Power Toler.
030 dBm 2dB 8 14 dBm 3dB
128 dBm 3dB 9 12 dBm 4dB
226 dBm 3dB 10 10 dBm 4dB
324 dBm 3dB 11 8 dBm 4dB
422 dBm 3dB 12 6 dBm 4dB
520 dBm 3dB 13 4 dBm 4dB
618 dBm 3dB 14 2 dBm 5dB
716 dBm 3dB 15 0 dBm 5dB

2. PERFORMANCE
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Item Description Specification
GSM, EGSM
Offset from Carrier (kHz). Max. dBc
100 +0.5
200 -30
250 -33
400 -60
600 ~ 1,200 -60
1,200 ~ 1,800 -60
1,800 ~ 3,000 -63
3,000 ~ 6,000 -65
5Output RF Spectrum 6,000 -71
(due to modulation) DCS
Offset from Carrier (kHz). Max. dBc
100 +0.5
200 -30
250 -33
400 -60
600 ~ 1,200 -60
1,200 ~ 1,800 -60
1,800 ~ 3,000 -65
3,000 ~ 6,000 -65
6,000 -73
GSM, EGSM
Offset from Carrier (kHz) Max. (dBm)
Output RF Spectrum 400 -19
6(due to switching transient) 600 -21
1,200 -21
1,800 -24

2. PERFORMANCE
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Item Description Specification
DCS
Offset from Carrier (kHz). Max. (dBm)
Output RF Spectrum 400 -22
6(due to switching transient) 600 -24
1,200 -24
1,800 -27
7Spurious Emissions Conduction, Emission Status
GSM, EGSM
8Bit Error Ratio BER (Class II) < 2.439% @-102 dBm
DCS
BER (Class II) < 2.439% @-100 dBm
9RX Level Report Accuracy 3 dB
10 SLR 8 3 dB
Frequency (Hz) Max.(dB) Min.(dB)
100 -12 -
200 0 -
300 0 -12
11 Sending Response 1,000 0 -6
2,000 4 -6
3,000 4 -6
3,400 4 -9
4,000 0 -
12 RLR 2 3 dB
Frequency (Hz) Max.(dB) Min.(dB)
100 -12 -
200 0 -
300 2 -7
500 *-5
13 Receiving Response 1,000 0 -5
3,000 2 -5
3,400 2 -10
4,000 2
*Mean that Adopt a straight line in between 300 Hz and
1,000 Hz to be Max. level in the range.

2. PERFORMANCE
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Item Description Specification
14 STMR 13 5 dB
15 Stability Margin > 6 dB
dB to ARL (dB) Level Ratio (dB)
-35 17.5
-30 22.5
-20 30.7
16 Distortion -10 33.3
033.7
731.7
10 25.5
17 Side Tone Distortion Three stage distortion < 10%
18 System frequency 2.5ppm
(13 MHz) tolerance
19 32.768KHz tolerance 30ppm
At least 65 dBspl under below conditions:
20 Ringer Volume 1. Ringer set as ringer.
2. Test distance set as 50 cm
21 Charge Current Fast Charge : < 430 mA
Slow Charge: < 160 mA
Antenna Bar Number Power
5-85 dBm ~
4-90 dBm ~ -86 dBm
22 Antenna Display 3 -95 dBm ~ -91 dBm
2-100 dBm ~ -96 dBm
1-105 dBm ~ -101 dBm
0~-105 dBm
Battery Bar Number Voltage
03.51V~3.61V
23 Battery Indicator 1 3.62V~3.69V
23.70V~3.77V
33.78V~3.91V
43.92V~
24 Low Voltage Warning 3.62 0.03V (Call)
3.50 0.03V (Standby)

2. PERFORMANCE
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Item Description Specification
25 Forced shut down Voltage 3.35 0.03 V
1 Li-ion Battery
26 Battery Type Standard Voltage = 3.7 V
Battery full charge voltage = 4.2 V
Capacity: 1000mAh
Switching-mode charger
27 Travel Charger Input: 100 ~ 240 V, 50/60Hz
Out put: 5.2V, 800mA

3. TECHNICAL BRIEF
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3.1 Transceiver (SI4205, U505)
The RF parts consist of a transmitter part, a receiver part, a frequency synthesizer part, a voltage
supply part, and a VCTCXO part.
The Aero I transceiver is the integrated RF front end for multi-band GSM/GPRS digital cellular
handsets and wireless data modems. The integrated solution eliminates the IF SAW filter, external low
noise amplifier (LNA) for three bands, transmit and RF voltage controlled oscillator (VCO) modules,
and other discrete components found in conventional designs.
3. TECHNICAL BRIEF
Figure. 3-1 RECEIVER FUNCTIONAL BLOCK DIAGRAM

3. TECHNICAL BRIEF
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(1) Receiver Part
The Aero I transceiver uses a low-IF receiver architecture which 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 architectures.
A. RF front end
RF front end consists of Antenna Switch(FL500), two SAW Filters(FL401, FL402) and dual band LNAs
integrated in transceiver (U505).
The Received RF signals(GSM 925MHz ~ 960MHz, DCS 1805MHz ~ 1880MHz) are fed into the
antenna or Mobile switch.
The Antenna Switch(FL500) is used to control the Rx and Tx paths. And, the input signals VC1 and
VC2 of a FL500 are directly connected to baseband controller to switch either Tx or Rx path on.
The logic and current is given below Table 3-1.
Three differential-input LNAs are integrated in SI4205. The GSM input supports the GSM 850 (824-849
MHz) or E-GSM 900 (925-960MHz) bands. The DCS input supports the DCS 1800 (1805-1880 MHz)
band. The PCS input supports the PCS 1900 (1930-1990 MHz) band.
The LNA inputs are matched to the 150 balanced output SAW filters through external LC matching
networks. The LNA gain is controlled with the LNAG[1:0] and LNAC[1:0] bits in register 05h (Figure 3-2).
VC1 VC2 Current
DCS Tx 0 V 2.5 ~ 3.0 V 10.0 mA max
GSM Tx 2.5 ~ 3.0 V 0 V 10.0 mA max
GSM / DCS Rx 0 V 0 V < 0.1 mA
Table 3-1 THE LOGIC AND CURRENT

3. TECHNICAL BRIEF
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B. Intermediate frequency (IF) and Demodulation
A quadrature image-reject mixer downconverts the RF signal to a 100KHz intermediate frequency (IF)
with the RFLO from the frequency synthesizer. The RFLO frequency is between 1737.8 to 1989.9
MHz, and is internally divided by 2 for GSM 850 and E-GSM 900 modes. The mixer output is amplified
with an analog programmable gain amplifier (PGA), which is controlled with the AGAIN[2:0] bits in
register 05h (Figure3-2). The quadrature IF signal is digitized with high resolution A/D converters
(ADCs).
The ADC output is downconverted to baseband with a digital 100KHz quadrature LO signal. Digital
decimation and IIR filters perform channel selection to remove blocking and reference interference
signals. The selectivity setting (CSEL=0) or a low selectivity setting (CSEL=1). The low selectivity filter
has a flatter group channelization filter is in the baseband chip. After channel selection, the digital
output is scaled with a digital PGA, which is controlled with the DGAIN [5:0] bits in register 05h.
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. No
special processing is required in the baseband for offset compensation or extended dynamic range.
Compared to a direct-conversion architecture, the low-IF architecture has a much greater degree of
immunity to dc offsets that can arise from RF local oscillator(RFLO) self-mixing, 2nd order distortion of
blockers, and device 1/f noise.
Figure. 3-2 SI4205 RECEIVER PART

3. TECHNICAL BRIEF
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(2) Transmitter Part
The transmit (Tx) section consists of an I/Q baseband upconverter, and offset phase-locked loop
(OPLL) and two output buffers that can drive external power amplifiers (PA), one for the GSM 850
(824-849 MHz) and E-GSM 900 (880-915 MHz) bands and one for the DCS 1800 (1710-1785 MHz)
and PCS 1900 (1850-1910MHz) bands.
A. IF Modulator
The baseband converter(BBC) within the GSM chipset generates I and Q baseband signals for the
Transmit vector modulator. The modulator provides more than 40dBc of carrier and unwanted
sideband rejection and produces a GMSK modulated signal. The baseband software is able to cancel
out differential DC offsets in the I/Q baseband signals caused by imperfections in the D/A converters.
The Tx-Modulator implements a quadrature modulator. A quadrature mixer upconverts the differential
in-phase (TXIP, TXIN) and quadrature (TXQP, TXQN) signals with the IFLO to generate a SSB IF
signal that is filtered and used as the reference input to the OPLL.
The IFLO frequency is generated between 766 and 896 MHz and internally divided by 2 to generate
the quadrature LO signals for the quadrature modulator, resulting in an IF between 383 and 448 MHz.
For the E-GSM 900 band, two different IFLO frequencies are required for spur management.
Therefore, the IF PLL must be programmed per channel in the E-GSM 900 band.
Figure. 3-3 SI4205 TRANSMITTER PART

3. TECHNICAL BRIEF
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B. OPLL
The OPLL consists of a feedback mixer, a phase detector, a loop filter, and a fully integrated TXVCO.
The TXVCO is centered between the DCS 1800 and PCS 1900 bands, and its output is divided by 2
for the GSM 850 and E-GSM 900 bands. The RFLO frequency is generated between 1272 and 1483
MHz. To allow a single VCO to be used for the RFLO, high-side injection is used for the GSM 850 and
E-GSM 900 bands, and low-side injection is used for the DCS 1800 and PCS 1900 bands. The I and Q
signals are automatically swapped when switching bands. Additionally, the SWAP bit in register 03h
can be used to manually exchange the I and Q signals.
Low-pass filters before the OPLL phase detector reduce the harmonic content of the quadrature
modulator and feedback mixer outputs. The cutoff frequency of the filters is programmable with the
FIF[3:0] bits in register 04h (Figure 3-3), and should be set to the recommended settings detailed in
the register description.

3. TECHNICAL BRIEF
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(3) Frequency Synthesizer
The Aero I 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. The output frequency of
each PLL is as follows:
fout = N x fø
The DIV2 bit in register 31h controls a programmable divider at the XIN pin to allow either a 13 or 26
MHz reference frequency. For receive mode, the RF1 PLL phase detector update rate (fø) should be
programmed fø= 100 kHz for DCS 1800 or PCS 1900 bands, and fø= 200 kHz for GSM 850 and E-
GSM 900 bands. For transmit mode, the RF2 and IF PLL phase detector update rates are always
fø =200 kHz.
Figure. 3-4 SI4205 FREQUENCY SYNTHESIZER PART

3. TECHNICAL BRIEF
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3.2 Power Amplifier Module (SKY77325, U501)
The SKY77325 Power Amplifier Module (PAM) is designed in a low profile (1.2 mm), compact form
factor for quad-band cellular handsets comprising GSM850/900, DCS1800, and PCS1900 operation.
The PAM also supports Class 12 General Packet Radio Service (GPRS) multi-slot operation.
The module consists of separate GSM850/900 PA and DCS1800/PCS1900 PA blocks, impedance-
matching circuitry for 50 input and output impedances, and a Power Amplifier Control (PAC) block
with an internal current-sense resistor. The custom BiCMOS integrated circuit provides the internal
PAC function and interface circuitry. Fabricated onto a single Gallium Arsenide (GaAs) die, one
Heterojunction Bipolar Transistor (HBT) PA block supports the GSM850/900 bands and the other
supports the DCS1800 and PCS1900 bands. Both PA blocks share common power supply pins to
distribute current. The GaAs die, the Silicon (Si) die, and the passive components are mounted on a
multi-layer laminate substrate. The assembly is encapsulated with plastic overmold.
RF input and output ports of the SKY77325 are internally matched to a 50 load to reduce the number
of external components for a quad-band design. Extremely low leakage current (2.5 A, typical) of the
dual PA module maximizes handset standby time. The SKY77325 also contains band-select switching
circuitry to select GSM (logic 0) or DCS/PCS (logic 1) as determined from the Band Select (BS) signal.
In Figure 3-5 below, the BS pin selects the PA output (DCS/PCS OUT or GSM850/900 OUT) and the
Analog Power Control (VAPC) controls the level of output power.
VBATT and VSENSE pins connect to an internal current-sense resistor and interface to an integrated
power amplifier control (iPAC¢‚) function, which is insensitive to variations in temperature, power
supply, process, and input power. The ENABLE input allows initial turnon of PAM circuitry to minimize
battery drain
3-5 Functional Block Diagram