LG C2100 User manual

Service Manual Model : C2100
Service Manual
C2100
P/N : MMBD0048201 Date: April, 2005 / Issue 1.0

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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 eatures.......................................... 9
2.2 Technical Specification ......................... 10
3. TECHNICAL BRIEF ....................... 15
3.1 Transceiver (SI4205, U505).................. 15
3.2 Power Amplifier Module
(SKY77325, U501)................................ 21
3.3 26 MHz Clock (VCTCXO, X500)........... 22
3.4 Power Supplies for R Circuits
(R LDO, U503).................................... 22
3.5 Digital Main Processor
(AD6527, U101) .................................... 23
3.6 Analog Main & Power Management
Processor (AD6537B, U102) ................ 29
3.7 Display and Interface ............................ 39
3.8 Keypad Switches and Scanning ........... 41
3.9 Microphone ........................................... 42
3.10 Main Speaker...................................... 42
3.11 Headset Interface................................ 43
3.12 Key Back-light Illumination.................. 44
3.13 LCD Back-light Illumination................. 45
3.14 VIBRATOR.......................................... 46
4. TROUBLESHOOTING ................... 47
4.1 RX Trouble............................................ 47
4.2 TX Trouble ............................................ 55
4.3 Power On Trouble................................. 63
4.4 Charging Trouble .................................. 65
4.5 Vibrator Trouble .................................... 67
4.6 LCD Trouble.......................................... 69
4.7 MIC Trouble .......................................... 71
4.8 SIM Card Interface Trouble................... 73
4.9 Earphone Trouble ................................. 75
4.10 KEY backlight Trouble ........................ 77
4.11 Receiver Trouble................................. 79
4.12 Microphone Trouble ............................ 81
4.13 RTC Trouble ....................................... 83
4.14 Indication LED Trouble ....................... 85
4.15 older on/off Trouble........................... 87
5. DOWNLOAD AND
CALIBRATION ............................... 89
5.1 Download .............................................. 89
5.2 Calibration............................................. 95
6. BLOC DIAGRAM ......................... 98
7. CIRCUIT DIAGRAM ....................... 99
8. PCB LAYOUT............................... 105
9. ENGINEERING MODE ................. 107
9.1 BB Test [MENU 1]............................... 108
9.2 R Test [MENU 2]............................... 109
9.3 M mode [MENU 3] ............................ 110
9.4 Trace option [MENU 4] ....................... 111
9.5 Call timer [MENU 5] ............................ 111
9.6 act. Reset [MENU 6] ......................... 111
9.7 S/W version......................................... 111
10. STAND ALONE TEST ................ 112
10.1 Introduction ....................................... 112
10.2 Setting Method.................................. 112
10.3 Means of Test ................................... 113
11. AUTO CALIBRATION................. 115
11.1 Overview ........................................... 115
Table Of Contents

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11.2 Requirements.................................... 115
11.3 Menu and Settings ............................ 115
11.4 AGC .................................................. 116
11.5 APC................................................... 116
11.6 ADC .................................................. 117
11.7 Setting............................................... 117
11.8 How to do calibration ........................ 117
12. EXPLODED VIEW &
REPLACEMENT PART LIST ........... 119
12.1 EXPLODED VIEW ............................ 119
12.2 Replacement Parts
<Mechanic component>.................... 121
<Main component> ........................... 123
12.3 Accessory ......................................... 135

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
or 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 milliwatt
DSP Digital Signal Processing
EEPROM Electrical Erasable Programmable Read-Only Memory
ESD Electrostatic Discharge
PCB lexible Printed Circuit Board
GMSK Gaussian Minimum Shift Keying
GPIB General Purpose Interface Bus
GSM Global System for Mobile Communications
IPUI International Portable User Identity
I Intermediate requency
LCD Liquid Crystal Display
LDO Low Drop Output
LED Light Emitting Diode
OPLL Offset Phase Locked Loop
PAM Power Amplifier Module
PCB Printed Circuit Board
PGA Programmable Gain Amplifier
PLL Phase Locked Loop
PSTN Public Switched Telephone Network
R Radio requency
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

1. INTRODUCTION
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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) x 53.55(H) x 5.7(T) [mm]
Battery Weight : 25g
Under the minimum current consumption
Stand by Current environment (such as paging period 9), the level of
standby current is below 4mA.
Talk time Up to 3 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 only
Display Main LCD : CSTN 128 x 160 pixel 65K Color
Sub LCD : STN 96 x 64 pixel MONO
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 E R/ R/HR
Data and ax 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
1 requency 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)
2 Phase Error RMS < 5 degrees
Peak < 20 degrees
3 requency Error < 0.1 ppm
GSM, EGSM
Level Power Toler. Level Power Toler.
5 33 dBm 2dB 13 17 dBm 3dB
6 31 dBm 3dB 14 15 dBm 3dB
7 29 dBm 3dB 15 13 dBm 3dB
8 27 dBm 3dB 16 11 dBm 5dB
9 25 dBm 3dB 17 9 dBm 5dB
10 23 dBm 3dB 18 7 dBm 5dB
11 21 dBm 3dB 19 5 dBm 5dB
4 Power Level 12 19 dBm 3dB
DCS
Level Power Toler. Level Power Toler.
0 30 dBm 2dB 8 14 dBm 3dB
1 28 dBm 3dB 9 12 dBm 4dB
2 26 dBm 3dB 10 10 dBm 4dB
3 24 dBm 3dB 11 8 dBm 4dB
4 22 dBm 3dB 12 6 dBm 4dB
5 20 dBm 3dB 13 4 dBm 4dB
6 18 dBm 3dB 14 2 dBm 5dB
7 16 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 R 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 R 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 R Spectrum 400 -22
6(due to switching transient) 600 -24
1,200 -24
1,800 -27
7 Spurious Emissions Conduction, Emission Status
GSM, EGSM
8 Bit Error Ratio BER (Class II) < 2.439% @-102dBm
DCS
BER (Class II) < 2.439% @-100dBm
9 Rx Level Report Accuracy 3 dB
10 SLR 8 3 dB
requency (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
requency (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
0 33.7
7 31.7
10 25.5
17 Side Tone Distortion Three stage distortion < 10%
18 System frequency
(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 ast 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
0 3.51V~3.61V
23 Battery Indicator 1 3.62V~3.69V
2 3.70V~3.77V
3 3.78V~3.91V
4 3.92V~
24 Low Voltage Warning 3.62 0.03V (Call)
3.50 0.03V (Standby)

2. PERFORMANCE
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Item Description Specification
25 orced 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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RF PARTS
3.1 Transceiver (SI4205, U505)
The R 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 R front end for multi-band GSM/GPRS digital cellular
handsets and wireless data modems. The integrated solution eliminates the I SAW filter, external low
noise amplifier (LNAs) for three bands, transmit and R voltage controlled oscillator (VCO modules,
and other discrete components found in conventional designs.
3. TECHNICAL BRIEF
Figure. 3-1 RECEIVER FUNCTIONAL BLOC DIAGRAM

3. TECHNICAL BRIEF
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(1) Receiver Part
The Aero I transceiver uses a low-I receiver architecture which allows for the on chip integration of
the channel selection filters, eliminating the external R image reject filters and the I SAW filter
required in conventional super-heterodyne architectures.
A. RF front end
R front end consists of Antenna Switch( L500), two SAW ilters( L401, L402) and dual band LNAs
integrated in transceiver (U505).
The Received R signals(GSM 925MHz ~ 960MHz, DCS 1805MHz ~ 1880MHz) are fed into the
antenna or Mobile switch.
The Antenna Switch( L500) is used to control the Rx and Tx paths. And, the input signals VC1 and
VC2 of a L500 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 150Ω 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 ( igure 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 R signal to a 100KHz intermediate frequency (I )
with the R LO from the frequency synthesizer. The R LO 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 ( igure3-2). The quadrature I 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-I architecture has a much greater degree of
immunity to dc offsets that can arise from R local oscillator(R LO) 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 I LO to generate a SSB I
signal that is filtered and used as the reference input to the OPLL.
The I LO 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 I between 383 and 448 MHz.
or the E-GSM 900 band, two different I LO frequencies are required for spur management.
Therefore, the I 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 R LO frequency is generated between 1272 and 1483
MHz. To allow a single VCO to be used for the R LO, 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
I [3:0] bits in register 04h ( igure 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 R PLL uses two multiplexed VCOs.
The R 1 VCO is used for receive mode, and the R 2 VCO is used for transmit mode. The I PLL is
used only during transmit mode. All VCO tuning inductors are also integrated. The I and R output
frequencies are set by programming the N-Divider registers, NR 1, NR 2 and NI . Programming the
NDivider register for either R 1 or R 2 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. or receive mode, the R 1 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. or transmit mode, the R 2 and I 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 (S Y77325, 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 Ω 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. abricated 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.
R input and output ports of the SKY77325 are internally matched to a 50 Ω load to reduce the
number of external components for a quad-band design. Extremely low leakage current (2.5 µA,
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 igure 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
Figure. 3-5 Functional Block Diagram