LG CX8550 Service Manual

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Page 1

Features of CX8550

1. Wave Type

CELLULAR : G7W

●

PCS: G7W

●

2. Frequency Scope Receive Frequency (MHz)Transmit Frequency (MHz)

3. Rated Output Power : CELLULAR = 0.25W

PCS = 0.25W

4. Output Conversion Method : This is possible by correcting the key board channel.

5. Voltage and Current Value of Termination Part Amplifier (Catalogue included)

PowerCurrentVoltagePart NameMODE

0.25W400mA4.2VAWT6321RCELLULAR

GPSPCSCELLULARPCSCELLULAR

1575.421930~1990869.82~893.191850~1910824.82 ~ 848.19

6. Functions of Major Semi-Conductors

Terminal operation control and digital signal processing MSM6500

Memory MCP

(TY9000A000BMGF)

7. Frequency Stability

CELLULAR : ±0.5PPM

●

● PCS : ±0.1PPM

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Flash Memory (1024Mbit) + SDRAM (512Mbit)

Storing of terminal operation program

Converts Rx RF signal to baseband signalRFR6500 Converts baseband signal to Tx RF signalRFT6150

0.25W400mA4.2VAWT6321RPCS

FunctionClassification

Page 2

CX8550

CDMA Mobile Subscriber Unit CX8550

SERVICE MANUAL

DUAL BAND CDMA

[PCS/Cellular/w/GPS]

CDMA MOBILE PHONE

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CX8550

Table of Contents

General Introduction……………………………………………………………………………...3

CHAPTER 1. System Introduction

1. CDMA Abstract…….………………………………………………………………….…….…..4

2. Features and Advantages of CDMA Mobile Phone…………....................................... . 5

3. Structure and Functions of Dual-band CDMA Mobile Phone……………………….…..8

4. Specification……………………………………………………………………………………..9

5. Installation………………………………………………………………………………………14

CHPATER 2. NAM Input Method

1. NAM Program Method and Telephone Number Inputting Method……………………16

CHAPTER 3. Circuit Description

1. RF Transmit/Receive Part……………………………………………………………….……26

2. Digital/Voice Processing Part……………………………………………………………….32

CHAPTER 4. Trouble Shooting………………………………………………………………...37

CHAPTER 5. Safety……………………………………………………………………..………133

CHAPTER 6. Glossary……………………………………………………………………….…136

APPENDIX…………………………………………………………………………………...……148

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CX8550

General Introduction

The CX8550 phone has been designed to operate on the latest digital mobile communication technology, Code Division Multiple Access (CDMA). This CDMA digital technology has greatly enhanced voice clarity and can provide a variety of advanced features. Currently, CDMA mobile communication technology has been commercially used in Cellular and Personal Communication Service (PCS). The difference between them is the operating frequency spectrum. Cellular uses 800MHz and PCS uses 1.9GHz. The CX8550 support GPS Mode, we usually call it tri-band phone. Also, CX8550 works on Advanced Mobile Phone Service (S-GPS). We call it dualmode phone. If one of the Cellular, PCS base stations is located nearby, Call fail rate of triple-mode phone is less than dual-mode phone or single-mode phone.

The CDMA technology adopts DSSS (Direct Sequence Spread Spectrum). This feature of DSSS enables the phone to keep communication from being crossed and to use one frequency channel by multiple users in the same specific area, resulting that it increases the capacity 1 0 times more compared with that in the analog mode currently used. Soft/Softer Handoff, Hard Handoff, and Dynamic RF power Control technologies are combined into this phone to reduce the call being interrupted in a middle of talking over the phone. Cellular and PCS CDMA network consists of MSO (Mobile Switching Office), BSC (Base Station Controller), BTS (Base station Transmission System), and MS (Mobile Station). The following table lists some major CDMA Standards.

Basic air interface

Network

Service

Performance

* TSB –74: Protocol between an IS-95A system and ANSI J-STD-008

TIA/EIA/IS-95-A/B/C

ANSI J-STD-008

TIA/EIA/IS-634 TIA/EIA/IS/651

TIA/EIA/IS-41-C

TIA/EIA/IS-124

TIA/EIA/IS-96-B

TIA/EIA/IS-99 TIA/EIA/IS-637 TIA/EIA/IS-657

TIA/EIA/IS-97

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TIA/EIA/IS-98

ANSI J-STD-018 ANSI J-STD-019

TIA/EIA/IS-125

Protocol between MS and BTS for Cellular & AMPS

Protocol between MS and BTS for PCS

DescriptionDesignatorCDMA Standard

MAS-BS

PCSC-RS

Intersystem operations

Nom-signaling data comm.

Speech CODEC

Assign data and fax

Short message service

Packet data

Cellular base station

Cellular mobile station

PCS personal station

PCS base station

Speech CODEC

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CX8550

Chapter1. System Introduction

1. CDMA Abstract

The CDMA mobile communication system has a channel hand-off function that is used for collecting the information on the locations and movements of mobile telephones from the cell site by automatically controlling several cell site through the setup of data transmission routes, and then enabling one switching system to carry out the automatic remote adjustment. This is to maintain continuously the call state through the automatic location confirmation and automatic radio channel conversion when the busy subscriber moves from the service area of one cell site to that of another by using automatic location confirmation and automatic radio channel conversion functions. The call state can be maintained continuously by the information exchange between switching systems when the busy subscriber moves from one Cellular system area to the other Cellular system area.

In the Cellular system, the cell site is a small-sized low output type and utilizes a frequency allocation system that considers mutual interference, in an effort to enable the re-use of corresponding frequency from a cell site separated more than a certain distance.

Unlike the time division multiple access (TDMA) or frequency division multiple access (FDMA) used in the band limited environment, the Code Division Multiple Access (CDMA) system which is one of digital Cellular systems is a multi-access technology under the interference limited environment. It can process more number of subscribers compared to other systems (TDMA system has the processing capacity three times greater than the existing FDMA system whereas CDMA system, about 12~15 times of that of the existing system).

CDMA system can be explained as follows; TDMA or CDMA can be used to enable each person to talk alternately or provide a separate room for each person when two persons desire to talk with each other at the same time, whereas FDMA can be used to enable one person to talk in soprano, whereas the other in bass (one of the two talkers can carry out synchronization for hearing in case there is a bandpass filter function in the area of the hearer). Another available method is to make two persons to sing in different languages at the same time, space, and frequency when wishing to let the audience hear the singing without being confused. This is the characteristic of CDMA.

On the other hand, when employing the CDMA technology, each signal has a different pseudo-random binary sequence used to spread the spectrum of carrier. A great number of CDMA signals share the same frequency spectrum. In the perspective of frequency area or time area, several CDMA signals are overlapped. Among these types of signals, only desired signal energy is selected and received through the use of pre-determined binary sequence; desired signals can be separated, and then received with the correlators used for recovering the spectrum into its original state. At this time, the spectrums of other signals that have different codes are not recovered into its original state, and appears as the self-interference of the system.

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2. Features and Advantages of CDMA Mobile Phone

2.1 Various Types of Diversities

When employing the narrow band modulation (30kHz band) that is the same as the analog FM modulation system used in the existing Cellular system, the multi-paths of radio waves create a serious fading. However, in the CDMA broadband modulation (1.25MHz band), three types of diversities (time, frequency, and space) are used to reduce serious fading problems generated from radio channels in order to obtain high-quality calls. Time diversity can be obtained through the use of code interleaving and error correction code whereas frequency diversity can be obtained by spreading signal energy to wider frequency band. The fading related to normal frequency can affect the normal 200~300KHz among signal bands and accordingly, serious effect can be avoided. Moreover, space diversity (also called path diversity) can be realized with the following three types of methods. First, it can be obtained by the duplication of cell site receive antenna. Second, it can be obtained through the use of multi-signal processing device that receives a transmit signal having each different transmission delay time and then, combines them. Third, it can be obtained through the multiple cell site connection (Soft Handoff) that connects the mobile station with more than two cell sites at the same time.

2.2 Power Control

The CDMA system utilizes the forward (from a base station to mobile stations) and backward (from the mobile station to the base station) power control in order to increase the call processing capacity and obtain high-quality calls. In case the originating signals of mobile stations are received by the cell site in the minimum call quality level (signal to interference) through the use of transmit power co ntrol on all the mobile stations, the system capacity can be maximized. If the signal power of mobile station is received too strong, the performance of that mobile station is improved. However, because of this, the interference on other mobile stations using the same channel is increased and accordingly, the call quality of other subscribers is reduced unless the maximum accommodation capacity is reduced. In the CDMA system, forward power control, backward open loop power control, and closed loop power control methods are used. The forward power control is carried out in the cell site to reduce the transmit power on mobile stations less affected by the multi-path fading and shadow phenomenon and the interference of other cell sites when the mobile station is not engaged in the call or is relatively nearer to the corresponding cell site. This is also used to provide additional power to mobile stations having high call error rates, located in bad receptio n areas or far away from the cell site. The backward open loop power control is carried out in a corresponding mobile station; the mobile station measures power received from the cell site and then, reversely increases/decreases transmit power in order to compensate channel changes caused by the forward link path loss and terrain characteristics in relation to the mobile station in the cell site. By doing so, all the mobile transmit signals received by the base station have same strength.

Moreover, the backward closed loop power control used by the mobile station is performed to control power using the commands issued out by the cell site. The cell site receives the signal of each corr esponding mobile station and compares this with the pre-set threshold value and then, issues ou t power in crease/decrease commands to the corresponding mobile station every 1.25msec (800 times per second). By doing so, the gain tolerance and the different radio propagation loss on the forward/backward link are complemented.

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CX8550

2.3 Voice Encoder and Variable Data Speed

The bi-directional voice service having variable data speed provides voice communication which employs voice encoder algorithm having power variable data rate between the base station and the mobile station. On the other hand, the transmit voice encoder performs voice sampling and then, creates encoded voice packets to be sent out to the receive voice encoder, whereas the receive voice encoder demodulates the received voice packets into voice samples.

One of the two voice encoders described in the above is selected for use depending on inputted automatic conditions and message/data; both of them utilize four-stage frames of 9600, 4800, 2400, and 1200 bits per second for Cellular and 14400,7200,3600,1800 bits per second for PCS, so PCS provide relatively better voice quality (almost twice better than the existing cellular system). In addition, this type of variable voice encoder utilizes adaptive threshold values on selecting required data rate. It is adjusted in accordance with the size of background noise and the data rate is increased to high rate only when the voice of caller is inputted.

Therefore, background noise is suppressed and high-quality voice transmission is possible under the environment experiencing serious noise. In addition, in case the caller does not talk, data transmission rate is reduced so that the transmission is carried out in low energy. This will reduce the interference on other CDMA signals and as a result, improve system performance (capacity increased by about two times).

2.4 Protecting Call Confidentiality

Voice privacy is provided in the CDMA system by means of the private long code mask used for PN spreading. Voice privacy can be applied on the traffic channels only. All calls are initiated using the public long code mask for PN spreading. The mobile station user may request voice privacy during call setup using the origination message or page response message, and during traffic channel operation using the long code transition request order. The Transition to private long code mask will not be performed if authentication is not performed. To initiate a transition to the private or public long code mask, either the base station or the mobile station send s a long code transition request order on the traffic channel.

2.5 Soft Handoff

A handoff in which the mobile station commences communications with a new base station without interrupting communications with the old base station. Soft handoff can only be used between CDMA channels having identical frequency assignments.

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2.6 Frequency Re-Use and Sector Segmentation

Unlike the existing analog Cellular system, the CDMA system can reuse the same frequency at the adjacent cell. there is no need to prepare a separate frequency plan. Total interference generated on mobile station signals received from the cell site is the sum of interference generated from other mobile stations in the same cell site and interference generated from the mobile station of adjacent cell site. That is, each mobile station signal generates interference in relation to the signals of all the other mobile stations.

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CX8550

Total interference from all the adjacent cell sites is the ratio of interference from all the cell sites versus total interference from other mobile stations in the same cell site (about 65%). In the case of directional cell site, one cell normally uses a 120°sector antenna in order to divide the sector into three. In this case, each antenna is used only for 1/3 of mobile stations in the cell site and accordingly, interference is reduced by 1/3 on the average and the capacity that can be supported by the entire system is increased by three times.

2.7 Soft Capacity

The subscriber capacity of the CDMA system is flexible depending on the relation between the number of users and

service classes. For example, the system operator can increase the number of channels available for use during the busy hour despite the drop in call quality. This type of function requires 40% of normal call channels in the standby mode during the handoff, in an effort to avoid call disconnection resulting from the lack of channels. In addition, in the CDMA system, services and service charges are classified further into different classes so that more transmit power can be allocated to high class service users for easier call set-up; they can also be given higher priority of using hand-off function than the general users.

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CX8550

3. Structure and Functions of tri-band CDMA Mobile Phone

The hardware structure of CDMA mobile phone is made up of radio frequency (RF) part and logic part. The RF part

is composed of Receiver part (Rx), Transmitter part (Tx) and Local part (LO). For the purp ose of operating on triband, It is necessary dual Tx path, tri Rx path, dual PLL and switching system for band selection. The mobile phone antenna is connected with the frequency separator which divide antenna input/output signals between Cellular frequency band (824~894 MHz) and PCS frequency band (1850~1990MHz). Each separated path is linked with the Cellular duplexer and PCS duplexer. Duplexer carries out separating Rx band and Tx band. The Rx signals from the antenna are converted into intermediate frequency(IF) band by the frequency synthesizer and frequency down converter. And then, pass SAW filter which is a band pass filter for removing out image frequency. The IF output signals that have been filtered is converted into digital signals via Analog-to-Digital Converter (ADC). In front of the ADC, switching system is required to choose which band path should be open. The digital signals send to 5 correlators in each CDMA de-modulator. Of these, one is called a searcher whereas the remaining 4 are called data receivers (fingers). Digitalized IF signals include a great number of call signals that have been sent out by the adjacent cells. These signals are detected with pseudo-noise sequence (PN Sequence). Signal to interference ratio (C/I) on signals that match the desired PN sequence are increased through this type of correlation detection process, but other signals obtain processing gain by not increasing the ratio. The carrier wave of pilot channel from the cell site most adjacently located is demodulated in order to obtain the sequence of encoded data symbols. During the operation with one cell site, the searcher searches ou t multi-paths in ac cordance with terrain and building reflections. On three data receivers, the most powerful 3 paths are allocated for the parallel tracing and receiving. Fading resistance can be improved a great deal by obtaining the diversity combined output for de-modulation. Moreover, the searcher can be used to determine the most powerful path from the cell sites even during the soft handoff between the two cell sites. Moreover, 3 data receivers are allocated in order to carry out the de-modulation of these paths. Output data that has been demodulated changes the data string in the combined data row as in the case of original signals(deinterleaving), and then, are demodulated by the forward error correction decoder which uses the Viterbi algorithm.

Mobile station user information send out from the mobile station to the cell site pass through the digital voice

encoder via a mike. Then, they are encoded and forward errors are corrected through the use of convolution encoder. Then, the order of code rows is changed in accordance with a certain regulation in order to remove any errors in the interleaver. Symbols made through the above process are spread after being loaded onto PN carrier waves. At this time, PN sequence is selected by each address designated in each call. Signals that have been code spread as above are digital modulated (QPSK) and then, power controlled at the automatic gain control amplifier (AGC Amp). Then, they are converted into RF band by the frequency synthesizer synchronizing these signals to proper output frequencies. Transmit signals obtained pass through the duplexer filter and then, are sent out to the cell site via the antenna.

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CX8550

4. Specification

4.1 General Specification

4.1.1 Transmit/Receive Frequency Interval :

1)CELLULAR : 45 MHz

2)PCS : 80 MHz

4.1.2 Number of Channels (Channel Bandwidth)

1)CELLULAR : 20 Channels

2) PCS : 48 Channels

4.1.3 Operating Voltage : DC 3.3~4.2V

4.1.4 Battery Power Consumption : DC 3.7V

MAX POWERIDLESLEEP

700 mA (24 dBm)110~180mA1.1 mA CELLULAR

4.1.5 Operating Temperature : -0°C ~ +60°C

4.1.6 Frequency Stability

1)CDMA : ±0.5PPM

2)PCS : ±0.1PPM

4.1.7 Antenna : Stubby Type (Helical), 50

4.1.8 Size and Weight

1)Size : 98.7(H) * 47.8(W) * 17.4(D) mm

2)Weight : 107 g (Approximately with standard battery)

4.1.9 Channel Spacing

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1)CELLULAR : 1.25MHz

2)PCS: 1.25 MHz

4.1.10 Battery Type, Capacity and Operating Time.

700 mA (24 dBm)120~180 mA1.1 mAPCS

Unit = Hours : Minutes

Talk time

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Standard (800mAh)

About 165 Hours (SCI=2)CELLULAR

Standby Time

About 165 Hours (SCI=2)PCS 140 Minutes (-92dBm input)CELLULAR 140 Minutes (-92dBm input)PCS

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CX8550

4.2 Receive Specification

4.2.1 Frequency Range

CELLULAR : 869.820 MHz ~ 893.190 MHz PCS : 1930 MHz ~ 1990 MHz GPS : 1575.42 MHz

4.2.2 Local Oscillating Frequency Range :

CELLULAR : 1738.08MHz ~ 1787.94MHz PCS : 1715.56MHz ∼ 1768.89MHz GPS : 3150.84MHz

4.2.3 Sensitivity

CELLULAR : -104dBm (C/N 12dB or more) PCS : -104dBm (C/N 12dB or more) GPS : -148.5dBm (without SA mode)

4.2.4 Selectivity

CELLULAR : 3dB C/N Degration (With Fch±1.25 kHz : -30dBm) PCS : 3dB C/N Degration (With Fch±1.25 kHz : -30dBm)

4.2.5 Spurious Wave Suppression : Maximum of -80dB

4.2.6 CDMA Input Signal Range

Dynamic area of more than -104~ -25 dB: 79dB at the 1.23MHz band.

4.3 Transmit Specification

4.3.1 Frequency Range

CELLULAR : 824.820MHz ~ 848.190MHz PCS : 1850 MHz ~ 1910 MHz

4.3.2 Output Power

CELLULAR : 0.224W PCS: 0.224W

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4.3.3 Interference Rejection

Single Tone : -30dBm at 900 kHz (CELLULAR), -30dBm at 1.25MHz(PCS) Two Tone : -43dBm at 900 kHz & 1700kHz(CELLULAR), -43dBm at 1.25 MHz & 2.05 MHz (PCS)

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CX8550

4.3.11 CDMA TX Frequency Deviation :

1) CELLULAR: +300Hz or less

2) PCS: ± 150Hz

4.3.12 CDMA TX Conducted Spurious Emissions

1) CELLULAR: 900kHz : - 42 dBc/30kHz below

1.98MHz : - 54 dBc/30kHz below

2) PCS: 1.25MHz: - 42 dBc/30kHz below

1.98MHz : - 50 dBc/30kHz below

4.3.13 CDMA Minimum TX Power Control

1) CELLULAR: - 50dBm below

2) PCS: -50dBm below

4.4 MS (Mobile Station) Transmitter Frequency

4.4.1 CELLULAR mode

1011

70 111 152 193 234 275 316 363

4.4.2 PCS mode

Ch #

Center Freq. (MHz)Ch #Center Freq. (MHz)Ch #

824.640

825.870

827.100

828.330

829.560

830.790

832.020

833.250

834.480

835.890

Ch #Center Freq

(MHz)

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404 445 486 527 568 609 650 697 738 779

Ch #Center Freq

(MHz)

837.120

838.350

839.580

840.810

842.040

843.270

844.500

845.910

847.140

848.370

Center Freq

(MHz)

1891.25 8251871.25 4251851.25 25

1892.50 8501872.50 4501852.50 50

1893.75 8751873.75 4751853.75 75

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1895.00 9001875.00 5001855.00 100

1896.25 9251876.25 5251856.25 125

1897.50 9501877.50 5501857.50 150

1898.75 9751878.75 5751858.75 175

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CX8550

4.5 MS (Mobile Station) Receiver Frequency

4.5.1 CELLULAR mode

1900.00 10001880.00 6001860.00 200

1901.25 10251881.25 6251861.25 225

1902.50 10501882.50 6501862.50 250

1903.75 10751883.75 6751863.75 275

1905.00 11001885.00 7001865.00 300

1906.25 11251886.25 7251866.25 325

1907.50 11501887.50 7501867.50 350

1908.75 11751888.75 7751868.75 375

Center Freq. (MHz)Ch. #Center Freq. (MHz)Ch. #

1011

70 111 152 193 234 275 316 363

4.5.2 PCS mode

869.640

870.870

872.100

873.330

874.560

875.790

877.020

878.250

879.480

880.890

Ch #Center Freq

(MHz)Ch #

404 445 486 527 568 609 650 697 738 779

Ch #Center Freq

(MHz)

882.120

883.350

884.580

885.810

887.040

888.270

889.500

890.910

892.140

893.370

Center Freq

(MHz)

1971.25 8251951.25 4251931.25 25

1972.50 8501952.50 4501932.50 50

1973.75 8751953.75 4751933.75 75

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1975.00 9001955.00 5001935.00 100

1976.25 9251956.25 5251936.25 125

LG Electronics Inc.

1977.50 9501957.50 5501937.50 150

1978.75 9751958.75 5751938.75 175

1980.00 10001960.00 6001940.00 200

1981.25 10251961.25 6251941.25 225

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4.5.3 GPS mode : 1575.42 MHz

4.5.4 Bluetooth mode : 2400 MHz ~ 2483.5 MHz

4.6 AC Adaptor : See Appendix

1982.50 10501962.50 6501942.50 250

1983.75 10751963.75 6751943.75 275

1985.00 11001965.00 7001945.00 300

1986.25 11251966.25 7251946.25 325

1987.50 11501967.50 7501947.50 350

1988.75 11751968.75 7751948.75 375

4.7 Cigar Lighter Charger : See Appendix

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5. Installation

5.1 Installing a Battery Pack

1) The Battery pack is keyed so it can only fit one way. Align the groove in the battery pa ck with the rail on the back of the phone until the battery pack rests flush with the back of the phone.

2) Slide the battery pack forward until you hear a “click”, which locks the battery in place.

5.2 For Adapter Use

1) Plug the adapter into a wall outlet. The adapter can be operated from a 110V source. When AC power is connected to the adapter.

2) Insert the adapter IO plug into the phone with the installed battery pack. Red light indicates battery is being charged.. Green light indicates battery is fully charged.

5.3 For Mobile Mount

5.3.1 Installation Position

In order to reduce echo sound when using the Hands-Free Kit, make sure that the speaker and microphone are not facing each other and keep microphone a generous distance from the speaker.

5.3.2 Cradle Installation

Choose an appropriate flat surface where the un it will not interface with driver’s movement or passenger’s comfort. The driver/user should be able to access the phone with ease. Using the four self-tapping screws provided, mount the supplied bracket on the selected area. Then with the four machine screws provided, mount the counterpart on the reverse side of the reverse side of the cradle. Secure the two brackets firmly together by using the two bracket joint screws provide. The distance between the cradle and the interface box must not exceed the length of the main cable.

5.3.3 Interface Box

Choose an appropriate flat surface ( somewhere under the dash on the passenger side is preferred ) and mount the IB bracket with the four self-tapping screws provided. Clip the IB into the IB bracket.

5.3.4. Microphone Installation

Install the microphone either by clipping I onto the sunvisor (driver’s side) or by attaching it to door post (driver’s side), using a velcro adhesive tape (not included).

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5.3.5 Cable Connections

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5.3.5.1 Power and Ignition Cables

Connect the red wire to the car battery positive terminal and the black wire to the car ground. Connect the green wire to the car ignition sensor terminal. ( In order to operate HFK please make sure to connect green wire to ignition sensor terminal.) Connect the kit’s power cable connector to the interface box power receptacle.

5.3.5.2 Antenna Cable Connection

Connect the antenna coupler cable connector from the cradle to the external antenna connector. ( Antenna is not included.)

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CX8550

CHAPTER 2. NAM Input Method

(Inputting of telephone numbers included)

1. NAM Programming Method

1) Press “##83587” and then, press “000000”

2) Press “1” key for entering “Service Programming.”.

● Usually pressing soft key will save the change.

● To exit service program, press “END” key.

3) NAM1 Setting

You can see the NAM1 setting.

Press softkey “OK” (Message key) to edit more NAM1 items. Press softkey “Exit” (Contacts) to exit Service Programming.

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4) NAM1 Phone Number (MDN)

You can edit the NAM1 Phone Number (MDN).

Press softkey “OK” (Message key) to edit more NAM1 items. Press softkey “Exit” (Contacts) to edit previous NAM1 items.

5) NAM1 Phone Number (MIN)

You can edit the NAM1 Phone Number (MIN).

Press softkey “OK” (Message key) to edit more NAM1 items. Press softkey “Back” (Contacts) to edit previous NAM1 items.

6) NAM1 Home SID

You can edit the NAM1 Home SID.

Press softkey “OK” (Message key) to edit more NAM1 items. Press softkey “Back” (Contacts) to edit previous NAM1 items.

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7) NAM1 Name

You can edit the NAM1 Name.

Press softkey “OK” (Message key) to edit more NAM1 items. Press softkey “Back” (Contacts) to edit previous NAM1 items.

8) More NAM1 Programming

You can decide to edit more NAM1 Name.

Press softkey “OK” (Message key) to exit Service Programming. Press softkey “More” (Contacts) to edit more advanced NAM1 items.

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9) NAM1 MCC

You can edit NAM1 Mobile Country Code.

Press softkey “OK” (Message key) to edit more NAM1 items. Press softkey “Back” (Contacts) to edit previous NAM1 items.

10) NAM1 NMSID

You can edit NAM1 NMSID.

Press softkey “OK” (Message key) to edit more NAM1 items. Press softkey “Back” (Contacts) to edit previous NAM1 items.

11) NAM1 True IMSI MCC

You can edit NAM1 True IMSI MCC.

Press softkey “OK” (Message key) to edit more NAM1 items. Press softkey “Back” (Contacts) to edit previous NAM1 items.

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12) NAM1 True IMSI NMSID

You can edit NAM1 True IMSI NMSID.

Press softkey “OK” (Message key) to edit more NAM1 items. Press softkey “Back” (Contacts) to edit previous NAM1 items.

13) NAM1 PRL Enabled

You can see NAM1 PRL Enabled.

Press softkey “OK” (Message key) to edit more NAM1 items. Press softkey “Back” (Contacts) to edit previous NAM1 items.

14) CDMA Home SID/NID

You can edit NAM1 Home SID/NID pair.

Press softkey “OK” (Message key) to edit more NAM1 items. Press softkey “Back” (Contacts) to edit previous NAM1 items.

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15) NAM1 CDMA Pri. CH A

You can edit NAM1 CDMA Pri. Channel A.

Press softkey “OK” (Message key) to edit more NAM1 items. Press softkey “Back” (Contacts) to edit previous NAM1 items.

16) NAM1 CDMA Sec. CH A

You can edit NAM1 CDMA Secondary Channel A.

Press softkey “OK” (Message key) to edit more NAM1 items. Press softkey “Back” (Contacts) to edit previous NAM1 items.

17) NAM1 CDMA Pri. CH B

You can edit NAM1 CDMA Primary Channel B.

Press softkey “OK” (Message key) to edit more NAM1 items. Press softkey “Back” (Contacts) to edit previous NAM1 items.

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CX8550

18) NAM1 CDMA Sec. CH B

You can edit NAM1 CDMA Secondary Channel B.

Press softkey “OK” (Message key) to edit more NAM1 items. Press softkey “Back” (Contacts) to edit previous NAM1 items.

19) Lockout SID/NID

You can edit Lockout SID/NID pair.

Press softkey “OK” (Message key) to edit more NAM1 items. Press softkey “Back” (Contacts) to edit previous NAM1 items.

20) NAM1 Home Sys. Reg.

You can edit NAM1 Home System Registration.

Press softkey “OK” (Message key) to edit more NAM1 items. Press softkey “Back” (Contacts) to edit previous NAM1 items. Press Left, Right, Up, Down key to toggle Yes/No.

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21) NAM1 Forn SID Reg

You can edit NAM1 Foreign SID Registration.

Press softkey “OK” (Message key) to edit more NAM1 items. Press softkey “Back” (Contacts) to edit previous NAM1 items. Press Left, Right, Up, Down key to toggle Yes/No.

22) NAM1 Forn NID Reg

You can edit NAM1 Foreign NID Registration.

Press softkey “OK” (Message key) to edit more NAM1 items. Press softkey “Back” (Contacts) to edit previous NAM1 items. Press Left, Right, Up, Down key to toggle Yes/No.

23) NAM1 ACC Ovld Class

You can edit NAM1 Access Overload Class.

Press softkey “OK” (Message key) to edit more NAM1 items. Press softkey “Back” (Contacts) to edit previous NAM1 items.

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CX8550

24) Slot Cycle Index

You can edit Slot Cycle Index.

Press softkey “OK” (Message key) to save Slot Cycle Index. Press softkey “Back” (Contacts) to edit previous items.

25) Powering Down

Restart.

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CX8550

CHAPTER 3. Circuit Description

1. RF Transmit/Receive Part

1.1 Overview

The TX and RX part employs the Direct-Conversion system. The TX and RX frequencies are respectively

824.04~848.97 and 869.04~893.97 for cellular and 1850~1910 and 1930~1990 for PCS. The block diagram is shown in [Figure 1-1]. CDMA RF signals received through the antenna are separated by the Diplexer. RF Signal fed into the low noise amplifier in RFR6500(LNA) through the duplexer. Then, they are fed into Mixer in RFR6500. In RFR6500, the RF signal is changed into baseband signal directly. Then, this signal is changed into digital signal by the analog to digital converter (ADC, A/D Converter), and the digital circuit part of the MSM(Mobile Station Modem) 6500 processes the data from ADC. The digital processing part is a demodulator. In the case of transmission, RFT6150 receives OQPSK-modulated analog signal from the MSM6500. The RFT6150 connects directly with MSM6500 using an analog baseband interface. In RFT6150, the baseband quadrature signals are upconverted to the Cellular or PCS frequency bands and amplified to provide signal drive capability to the power amp. After that, the RF signal is amplified by the Power Amp in order to have enough power for radiation. Finally, the RF signal is sent out to the cell site via the antenna after going through the duplexer.

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CX8550

[Figure 1-1] RF Block Diagram of CX8550

Logic

Device

RF Part

8550

Block Diagram

MSM

MSM Core

Tx_I

B9003

F104

R 6320

AWT

, CMX

, QCELP

1_I Rx

MP3, AAC,

AMR

EVRC

Secondary Path

MIDI

1_Q Rx

Audio

.264

®ES

Video

263

MPEG-4

Graphics

VCO

Diversity Rx

D, 2D

OpenGL

GPS VCO

LO Gen

Camera

Processing

for GPS

Loop Filter

PLL1

ref

&Dist

U110

F102

GPS BPF

-1575M5UB02 14

gpsOne

Processor

PLL

Processor

Bluetooth

Loop Filter

Tx DAC

Processor

Buffer

TC7SZ04FU

for CDMA Tx

SBI

TCXO

Rx ADC

. Ref

X100

KT22P-DCW28A-19.200M-T

EBI2

EBI1

Buses

Dual Memory

SBI Control

ref

1X,

4000

with Jazelle

PLL

4000

Modem

QDSP

926EJS

JTAG I/F

ARM

GPRS

CDMA

1X EV

GSM

Processor

Processors

SBI Control

&Controls Digital I/Os

Tx VCO

LO Gen &Dist

Rx VCO

Diversity

SDIO

UART1

Keypad I/

USB On The

UART2/RUIM1

Connectivity

MSM6500

0 Rx

&Controls

Digital I/Os

Gen

&Dist

UART3/RUIM2

0_Q Rx

Primary Path

U111

Gain

Circuits

Control

BPF

PCS

DCN

1G8800-

FAR-F6KA-

RFT6150

4AF

F103

PLL0

CDMA VCOs

FAR-G6KE-

F101

Dual BPF

1G9600-Y4LY

RFR6500

High

DCN

PCS

Dual PAM

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Efficiency

U107

Loop Filter

for CDMA Rx

DCN

1880ENTR

Coupler

A 0402

LG Electronics Inc.

HDET

LMV228TLX-NOPB

PCS

Coupler

A1880ENTR 0402

7637 B

DP100

xRx

DCN

Duplexer

CDMA

Antenna

xRx

ipl

exe r

PCS

CDMA RF

Duplexer

connector

FSLF-080HR

ACMD-7402

F105

GPS

Antenna

DP101

GPS RF

connector

GPS

Pre-LNA

BPF

GPS

14-1575M5UB02 SF

Directly connected to

U104

ALM1106-TR1

B7839

F100

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CX8550

1.2 Description of RX Part Circuit

1.2.1 Diplexer (F105)

The main function of Diplexer is to prohibit the other band signals from flowing into the one band circuit and vice versa. RF designer can use common tri-band antenna regardless of frequency band (800, 1575 and 1900 MHz). The specification of CX8550 Diplexer is described below:

PCSCellular

1850 – 1990 MHz824 – 894 MHzFrequency Range

Insertion Loss to

Common

Isolation

1.2.2 Duplexer (DP100, DP101)

The duplexer consists of the RX bandpass filter (BPF) and the TX BPF which has the function of separating TX and RX signals in the full duplex system for using the common antenna. The TX part BPF is used to suppress noises and spurious out of the TX frequency band. The RX BPF is used to receive only RX signal coming from the antenna, which is usually called preselector. It’s main function is to limit the bandwidth of spectrum reaching the LNA and mixer, attenuate receiver spurious response and suppress local oscillator energy. As a result frequency sensitivity and selectivity of mobile phone increase. The specification of CX8550 duplexer described below ;

z PCS duplexer:

0.5 dB Max

(At +25 deg)

18 dB Min (to PCS)

-30 to +85 degTemperature Range

1930~1990 MHz1850~1910 MHzPass Band

0.6 dB Max

(At +25 deg)

18 dB Min (to Cellular)

TX to RX (min)RXTX

z Cellular duplexer

LG Electronics Inc.

3.0dB max3.5dB maxInsertion Loss

9.5dB min9.5dB minReturn Loss

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43dB min (1930~1990MHz)Attenuation

54dB min (824~849MHz)45dB min (869~894MHz)Attenuation

52dB min

(1850~1910MHz)

869~894 MHz824~849 MHzPass Band

3.5dB max2.3B maxInsertion Loss 8dB min9dB minReturn Loss

54dB (1850~1910MHz)

45dB (1930~1990MHz)

TX to RX (min)RXTX

55dB (824~849MHz)

47dB (869~894MHz)

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CX8550

1.2.3 RFR6500 – LNA part (U110)

The RFR6500 has cellular, and PCS LNA, respectively. The characteristics of Low Noise Amplifier (LNA) are low noise figure, high gain, high intercept point and high reverse isolation. The frequency selectivity characteristic of mobile phone is mostly determined by LNA. The specification of CX8550 LNA is described below:

PCSCellularPCSCellularPCSCellular

1.2.4 GPS LNA(U104)

The characteristics of Low Noise Amplifier (LNA) are low noise figure, high g ain, high intercept p oint and high reverse isolation. The frequency selectivity c haracteristic of mobile phone is mostly determined by LNA. The specification of CX8550 GPS LNA is described below

UnitsHigh gainMiddle gainLow gainParameter

dB1514-33-20-19Gain dB1.11.364.52020Noise Figure

dBm371051010Input IP3

UnitsGPS BandParameter

dB14.3Gain

dB0.8Noise Figure dBm1.81dB compression point dBm+4.7IIP3

1.2.5 RX RF SAW FILTER(F101, F102)

The main function of RX RF SAW filter is to attenuate mobile phone spurious frequency, attenuate noise amplified by the LNA and suppress second harmonic originating in the LNA.

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1.2.6 RFR6500 - Down-converter Mixers part (U110)

The RFR6500 device performs signal down-conversion for Cellular, PCS and GPS tri-band applications. It contains all the circuitry (with the exception of external filters) needed to support conversion of received RF signals to Baseband signals. The three down-converting Mixers (Cellular, PCS and GPS), and a programmable PLL for generating RX LO frequency and an RX LO Buffer Amplifier and RX Voltage Controlled Oscillator. The GPS LNA & mixers offer the most advanced and integrated CDMA RX solution designed to meet cascaded Noise Figure (NF) and Thirdorder Intercept Point (IIP3) requirements of IS-98D and J-STD-018 specifications for Sensitivity, Two-Tone Intermodulation, and Single-tone Desensitization. Operation modes and band selection are specially controlled from the Mobile Station Modem MSM6500. The specification of CX8550 Mixers is described below:

UnitsHigh gainLow gainParameter

PCSCellularPCSCellular

dB127.92725Noise Figure

dBm44-11-5Input IP3

dBm56563030Input IP2

1.3 Description of Transmit Part Circuit

1.3.1 RFT6150 (U111)

The RFT6150 Base-band to RF Transmit Processor performs all TX signal-processing functions required between digital Base-band and the Power Amplifier Modulator (PAM). The Base-band quadrate signals are up-converted to the Cellular or PCS frequency bands and amplified to provide signal drive capability to the PAM. The RFT6100 includes mixers for up-converting analog Base-band to RF, a programmable PLL for generating TX LO frequency a TX LO Buffer Amplifier and TX Voltage Controlled Oscillator, cellular and PCS driver amplifiers and TX power control through an 85 dB VGA. As added benefit, the single sideband up-conversion eliminates the need for a band pass filter normally required between the up-converter and driver amplifier.

I, I/, Q and Q/ signals proceed from the MSM6500 to RFT6150 are analog signal. In CDMA mode, These signals are modulated by Offset Quadrature Phase Shift King (OQPSK). I and Q are 90 deg. out of phase, and I and I/ are 180 deg. The mixers in RFT6150 converts baseband signals into RF signals. After passing through the upconverters, RF signal is inputted into the Power AMP.

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CX8550

zRFT6150 Cellular and PCS CDMA RF Specifications

UnitsMax.Type.Min.ConditionParameter

Rated Output Power

Min Output Power

RX band noise power

ACPR

1.3.2 Power Amplifier(U107)

The Dual power amplifier that can be used in the PCS and CDMA mode has linear amplification capability and high efficiency. For higher efficiency, it is made up of one MMIC (Monolithic Microwave Integrated Circuit) for which RF input terminal and internal interface circuit are integrated onto one IC after going thro ugh the AlGaAs/GaAs HBT (heterojunction bipolar transistor) process. The module of power amplifier is made up of an output end interface circuit including this MMIC. The maximum power that can be inputted through the input terminal is +10dBm and conversion gain is about 26.5dB. RF transmit signals that have been amplified through the power amplifier are sent to the duplexer. .

Average CDMA Cellular

Average CDMA PCS

Average CDMA Cellular

Average CDMA PCS

CDMA Cellular

CDMA PCS

Cellular: Fc±885kHz

PCS : Fc±1.25MHz

7 9

-75

-136

-133

-56

-57

dBm dBm

dBm/Hz

dBc/30kHz

1.4 Description of Frequency Synthesizer Circuit

1.4.1 Voltage Control Temperature Compensation Crystal Oscillator (VCTCXO, X100)

The temperature variation of mobile phone can be compensated by VCTCXO. The reference frequency of a mobile phone is 19.2 MHz. The receiver frequency tuning signals called TRK_LO_ADJ from MSM as 0.5 V~2.5 V DC via R and C filter in order to generate the reference frequency of 19.2 MHz and input it into the frequency synthesizer. Frequency stability depending on temperature is ±2.0 ppm.

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2. Digital/Voice Processing Part

2.1 Overview

The digital/voice processing part processes the user's commands and processes all the digital and voice signal processing in order to operate in the phone. The digital/voice processing part is made up of a main keypad/touch keypad/LCD, receptacle part, voice processing part, mobile station modem part, memory part, and power supply part.

2.2 Configuration

2.2.1 Keypad/LCD and Receptacle Part

This is used to transmit keypad signals to MSM6500. It is made up of a keypad backlight part that illuminates the keypad, LCD part that displays the operation status onto the screen, and a receptacle that receives and sends out voice and data with external sources.

2.2.2 Voice Processing Part

The voice processing part is made up of an audio codec used to convert MIC signals into digital voice signals and digital voice signals into analog voice signals, amplifying part for amplifying the voice signals and sending them to the ear piece, amplifying part that amplifies ringer signals coming out from MSM6500, and amplifying part that amplifies signals coming out from MIC and transferring them to the audio processor.

2.2.3 MSM (Mobile Station Modem) 6500 Part

MSM is the core elements of CDMA terminal and carries out the functions of CPU, encoder, interleaver, deinterleaver, Viterbi decoder, Mod/Demod, and vocoder.

2.2.4 Memory Part

The memory part is made up of a NAND Flash memory and a SDRAM for storing data.

2.2.5 Power Supply Part

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The power supply part is made up of circuits for generating various types of power, used for the digital/voice processing part.

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2.3 Circuit Description

2.3.1 Keypad/LCD and Receptacle Part

Once the main keypad is pressed, the key signals are sent out to MSM6500 for processing. Touch keypad is pressed, I2C and Ack signals of U101(touch IC) are sent out to MSM6500 for processing. In addition, when the key is pressed, the keypad/LCD lights up through the use of 19 LEDs. The terminal status and operation are displayed on the screen for the user with the characters and icons on the LCD. Moreover, it exchanges audio signals and data with external sources through the receptacle, and then receives power from the battery or external batteries.

2.3.2 Audio Processing Part

MIC signals are amplified through OP AMP, inputted into the audio codec (included in MSM6500) and converted into digital signals. Oppositely, digital audio signals are converted into analog signals after going through the audio codec. These signals are amplified at the audio amplifier and transmitted to the ear-piece. The signals from MSM6500 activate the ringer by using signals generated in the timer in MSM6500.

2.3.3 MSM Part

MSM6500 is the core element of CDMA system terminal that includes ARM926EJ-S microprocessor core. It supports both CDMA and Digital FM, operating in both the cellular and PCS spectrums. The subsystems within the MSM6500 include a CDMA processor, a DFM processor, a multi-standard Vocoder, an integrated CODEC with earpiece and microphone amplifiers, general-purpose ADC for subsystem monitoring, an ARM926EJ-S microprocessor, and an RS-232 serial interfaces supporting forward and reverse link MDR data communications of

230.4 Kbps simultaneously. And it also contains complete digital modulation and demodulation systems for both CDMA and AMPS cellular standards, as specified in IS-95-A/B/C. In MSM, coded symbols are interleaved in order to cope with multi-path fading. Each data channel is scrambled by the long code PN sequence of the user in order to ensure the confidentiality of calls. Moreover, binary quadrature codes are used based on Walsh functions in order to discern each channel. Data created thus are 4-phase modulated by one pair of Pilot PN code and they are used to create I and Q data. When received, I and Q data are demodulated into symbols by the demodulator, and then de-interleaved in reverse to the case of transmission. Then, the errors of data received from Viterbi decoder are detected and corrected. They are voice-decoded at the Vocoder in order to output digital voice data.

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CX8550

800

CODEC YMU

MIC IN

AGC

48kHz sampling

ADC

Separate volume control(L, R)

A- IN

Mono

Stereo

[Figure 2-2] Block Diagram of Digital/Voice Processing Part

from

MSM

I2C

HP amp

B-Register

Stereo HP amp

700mW

Class D

Speaker amp

Mono/Digital

Non-clip by S

TCXO

Buffered

Sampling Rate

I2S D-IN

)

Converter(SRC

8 ~ 48kHz rate

LCD

AGC

Audio Engine DSP

HPF

’’

2.0

QVGA

16bit

3D Surround

Fade In/Out

Wide View

Karaoke

Noise Gate

Peak Indicator

Bass Boost

Compressor

Micro SD

bit

(10 Band)

Band Expander

Digital Equalizer

Spectrum Indicator(7 Band)

512Mbit

bit Stereo 16

192kHz sampling

frequency

Pitch Change

DAC

Voice/

Dynamic Range Control(DRC)

JIB0

NAND

U0C

I2S D- OUT

1208 K9F

8bit

1.3M CMOS,

Image Sensor

8bit

MIC

MMI

18pin

4pole

To MSM

From HP amp

MAX 9722 B

Mono Speaker

size

1813

4pole Earjack

To MSM: Voice Call

Stereo Headset

HS) 0

Logic Part

Block Diagram

CX8550

To CODEC: Recording flix

DSP

DSP Core

512MBit

MCP

EBI1

MSM

MSM Core

Power

PMIC LP3919

8bit ADC for

)

LCD Bypass

(MPEG4/H.263

926EJ-S

clock up to 192MHz

H/W Video Codec

Max.

PLL

1GBit

EBI2

DMA Controller

NAND

Memory

9000A000AMGF TY

8bit

ARM

SDRAM

16bit

PLL

JTAG I

Li-Ion Linear

Modem

QDSP4000

with Jazelle

ARM926EJS

/DC

RESET

XDC

battery

LDOX9

Charger Control

Thermal Shutdown

Momentary Power Loss

Peripheral I/

RB04

/RUIM2

UART3

Duplexer

ANT.

CDMA

UART

Bluetooth

RF Module

, AAC,

Audio

RFR6500

GPIO

USB 2.0 with HS /FS

PWM

SPI1/SPI2 I2

TCXO

Buffered

Bluetooth v1.1

QCELP

, CMX, AMR

EVRC,

Loop

L_IN

_ P

RF to BB

Converter

TxRx

MIDI

Filter

)

D Graphic

LCD 8/12 /16 /18 bit

Dual Memory

SBI

BB to RF

Converter

DCN

SAW

Dual

PAM

DCN

PIP

OSD, Overlay, BitBLT

Image Sensor I

Picture In Picture(

2D Accelerator

DN01

Jog Wheel

B5V-14202-

EBI1EBI

Buses

DCN

Filter

HDET

Coupler

YUV 422 Format

CMOS or CCD with QSXGA(5M) to CIF

(AAT3123)

Charge Pump

6500

Connectivity

MSM

Filter

Loop

for CDMA

PCS

Coupler

GPIO & 4*

SAW

High

4*AAT4290)

Expander(

Keypad I

Filter

Efficiency

I2S In/Out

Audio I/F

AMR-NB, G723.1 , WA V

128 voices MIDI Synthesizer

Encoding: AAC, MP3, AMR-NB, WAV

Decoding: AAC, AAC +, MP 3, WMA , RA,

Light

Wheel

Dual LED*8

HSMF-C16x

/RUIM1

1.1 FS

SDIO

UART1

USB

UART2

CODEC

Bluetooth

Buffer

PCS

TCXO

NAND I

MOVI NAND

Storage I

, GB

8635

Mbit SDRAM 64

Video

Still Image

VLC/VLD BIT pack/unpack

NAND Flash Up to

SD/MMC/T-Flash

Memory Controller

Host I/

EBI2

of I/O

high or

in order

Needs to

16bit

pulled to

low during

SO240000

not to be

sleep state

would be

that state

make sure

Key

Touch

Sensor

Rotation

Superimpose

QSXGA(5M) to CIF image size

JPEG En/Decoding up to QSXGA

Color Effect

Digital Zoom X

floated

Keypad

1X,

Z3X-BOX.COM

/GPRS

CDMA

QDSP4000

USB TCVR

Processor

Processors

XComparator

Separate LD O

Detection

ON/OFF Control & I2C I

gpsOne

1X EV-DO

Processor

GSM

for CAM

3*LDO(RI1114D)

RI1180D)

(

6* LDO

5V USB(380mA)

550mA)

(

Dual Charger ISL6299A

for DSP

5V Craddle

SBI

Tx DAC

Rx ADC

Processor

Bluetooth 1.1

TXI

TXQ

6150 RFT

RF Front End

with mass storage or MTP

for GPS

L_IN

_ G

CDMA

Receiver

Video

OUT _L_

TxRx

Diplexer

Mobile

18pin MMI

MIC IN

-4

MPEG

SBI

DCN

From HP amp

Stereo Headset

A-OUT

EAR MIC IN

.264 H

, 263

OUT L_

L_IN

Duplexer

RX0I

To MSM

Graphics

OUT L_

_ D

GPS

UART up to

To MSM(USB 1.1 FS)

To DSP(USB 2.

music file into DSP NAND)

(Dedicated to transfer

USB

Motor

468kbps

USB 1.1 FS

& Support Vib-

®ES

, 2D D

Camera

OpenGL

RX1I

RX1Q

RX0Q

P_IN

filter

SAW

Dual RX

ANT

To MSM

To Charger IC

UART

CHARGER

Touch

PDM

Processing

IN _ G

Filter

GPS SAW

GPS

Mobile

GPS

LNA

Filter

GPS SAW

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CX8550

2.3.4 Memory Part

MCP contents 1Gbits NAND FLASH memory and 512Mbits SDRAM. In the NAND Flash Memory part of MCP are programs used for terminal operation. The programs can be changed through downloading after the assembling of terminals. On the SDRAM data generated during the terminal operation are stored temporarily.

2.3.5 Power Supply Part

When the battery voltage (+4.0V) is fed and the PWR key of keypad is pressed, U303(PMIC) is activated by the PWR_ON_SW signal, and The PWRON signal is held high, Buck and LDO1,2,3 are turned on; when LDO1 reaches 87% of its final value a 60ms reset timer is started at after which RESET\ is asserted high. Now the BB Processor is initialized and will assert PWRHOLD high. PWRHOLD maintains the power on.

The Buck/LDO1,2,3 are generating the +1.4V_MSMC, +2.6V_MSMA, +1.8V_MSMP1 and +2.8V_LCD respectively.

The Rx part LDO(Out5) is operated by the control signal SLEEP/ from MSM6500

The Tx part LDO(Out4) is operated by the control signal IDLE/ from MSM6500.

The TCXO part LDO(Out7) is operated by the control signal TCXO_EN/ from MSM6500.

2.3.6 Logic Part

The logic part consists of internal CPU of MSM, RAM, MCP. The MSM6500 receives TCXO (=19.2MHz) from the X100 and controls the phone in CDMA modes. The major components are as follows:

CPU

The ARM926J-S microprocessor includes a 3 stage pipelined RISC architecture, both 32-bit ARM and 16-bit THUMB instruction sets, a 32-bit address bus, and a 32-bit internal data bus. It has a high performance and low power consumption.

MCP

NAND Flash is used to store the terminal’s program. Using the down-loading program, the program can be changed even after the terminal is fully assembled.

SDRAM is used to store the internal flag information, call processing data, and timer data.

KEYPAD

For key recognition, key matrix is setup using KYPD[1][3][5][7][9][11][13][15][17]signal from MSM6500. 2 LEDs and backlight circuitry are included in the keypad for easy operation in the dark.

TOUCH KEYPAD

For key recognition, U106 communicates with MSM6500 by using TOUCH_DATA, TOUCH_CLK, TOUCH_ACK. 4 LEDs and backlight circuitry are included in the keypad for easy operation in the dark. Touch keypad also supports vibe-touch function when pressing is recognized.

LCD MODULE

LCD module contains a controller which will display the information onto the LCD by 16-bit data from the MSM6500. It is also supplied stable +2.8V_LCD by Out3 in U303 for fine view angle and LCD reflects to

improve the display efficiency. 3 LEDs is used to display LCD backlight.

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CX8550

2.3.7 DSP (Multimedia processor) Part

DSP is a specialized integrated circuit that encompasses efficient camera functions, MPEG4 simple profile level 3 compliant codec functions. The host’s register setting by executed with 2-bit address bus, 1-bit chip select signal, 1bit write enable signal, 1-bit read enable signal and 16-bit data bus from the host(MSM6500). DSP contained the advanced ARM9. ARM9 is a member of the ARM family of general-purpose 32-bit microprocessors.

LCD

In the bypass mode, MSM has complete control over all LCD operations, excluding camera processing function. In other words, it indicates when LCD is initialized and GUI of system is displayed on the LCD.

CAMERA

DSP provides clock to operate sensor and controls internal register of sensor through the I2C master embedded in DSP to make sensor operate normally. After completion of internal register setting, sensor supplies YUV422 image data, synchronous signal and pixel clock synchronized with pixel of image data to DSP. VSYNC is a synchronized signal to differentiate frames and HREF is a synchronized signal to differentiate lines. These signals are synchronized with the pixel clock. Input image data through the sensor interfac e is previewed on the LCD up to 30fps through the IMAGE ENHANCER.

EXTERNAL CODEC

Normally codec bypass signal from MSM6500 to Speaker, Receiver or Headset. However, when we listen to the music in “My Music” folder codec performs 3-D sound enhancement and automatic level control for microphone or line input. The on-chip ADC and DAC are of a high quality using a multi-bit, low-order oversampling architecture to deliver optimum performance with low power consumption. It supports I2S audio data format between DSP and codec. A speaker amplifier, using digital amplifier system, realizes low power consumption than that of linear amplifier. In addition, power-down mode is available to minimize the current consumption when used.

Z3X-BOX.COM

LG Electronics Inc.

- 35/147 -

Page 37

CX8550

4.1 Rx Part Trouble

4.1.1 DCN Rx

CHAPTER 4. Trouble Shooting

Test Point

Mobile S/W

Diplexer

DCN_Duplexer

Start

Rx TEST SETUP (HHP)

- Test C hann el : 38 4

- Test Band: US Cellular

- SID: 2004

- Sector Power : -30 dBm Spectrum Analyz er Setting

Oscilloscope Setting

DC Power Supply circuit

Z3X-BOX.COM

1. Check

VCTCXO

RFR6500

Check flow

3. Check

Control signal

4. Check

RF Signal path

LG Electronics Inc.

2. Check VCTCXO

5. Check

Rx I/Q data

Redownload S/W, Cal

- 36/147 -

Page 38

CX8550

4.1.1.1 Checking DC Power supply circuit (PMIC)

Test Point

R328

Circuit Diagram

R330

TP1

TP2

Z3X-BOX.COM

LG Electronics Inc.

- 37/147 -

Page 39

CX8550

Start

Checking Flow

Check R330

+2.9V_RX is OK?

YES

Check R328

+2.6V_MSMP2 is OK?

YES

DC Power supply Circuit is OK. See next Pagetocheck

VCTCXO circuit

The Problem may be Logic part

Refer to Logic troubleshoot

The Problem may be Logic part

Refer to Logic troubleshoot

LG Electronics Inc.

Z3X-BOX.COM

- 38/147 -

Page 40

CX8550

4.1.1.2 Checking VCTCXO circuit

Test Point

X100 pin3

X100 pin4

Circuit Diagram

TP2

TP1

Z3X-BOX.COM

LG Electronics Inc.

- 39/147 -

Page 41

CX8550

Start

Checking Flow

Check X100 pin3

Is it 19.2MHz? (Refer to

figure 4.1.1 (a))

Check X100 pin4

Is it 2.8V? (Refer to

figure 4.1.1 (b))

YES

Replace X100 and then check C152, R107.

Is it similar?

Replace Main B /D

VCTCXO circuit is Ok . See next page

YES

to check control signal .

Th e Pro ble m may be Logic par t

Refer to Logic troubleshoot

VCTCXO circuit is Ok . See next page

to check control signal .

Figure 4.1.1 (a)

LG Electronics Inc.

Waveform

Z3X-BOX.COM

Figure 4.1.1 (b)

- 40/147 -

Page 42

CX8550

4.1.1.3 Checking Control signal

U110 pin49(SBST0)

pin50(SBDT0) pin51(SBCK0)

Test Point

Circuit Diagram

Z3X-BOX.COM

LG Electronics Inc.

- 41/147 -

Page 43

CX8550

Start

Checking Flow

Check if there is any major difference referring

Check pin49, 50, 51 at U110

To Figure 4.1.1 (c), (d)

Redownload S/W

Check pin49, 50, 51 at U110

To Figure 4.1.1 (c), (d)

Replace Main B /D

Waveform

YES

Control signal is Ok . See next page

to check RF signal path .

Control signal is Ok . See next page

to check RF signal path .

Figure 4.1.1 (c)

LG Electronics Inc.

Z3X-BOX.COM

Figure 4.1.1 (d)

- 42/147 -

Page 44

CX8550

4.1.1.4 Checking RF signal path (Mobile S/W, Diplexer, Duplexer)

Test Point

F105.

U10

1. Pin2

C103, L103

Pin6

DP100. Pin3

L104, L139

L117, C126 L125, C136

TP1

Circuit Diagram

PCS Tx DCN Tx PCS Rx DCN Rx

Z3X-BOX.COM

TP2

TP3

LG Electronics Inc.

- 43/147 -

Page 45

CX8550

Start

Checking Flow

Check if there is any major difference referring

Check pin2 at U101

To Figure 4.1.1 (e). Is any signal detected at

that point?

YES

Is any signal detected at

that point?

YES

Check pin6 at F105

Check if there is any major difference referring

To Figure 4.1.1 (f). Is any signal detected at

that point?

YES

Is any signal detected at

that point?

Replace U101

Check C103, L103

Replace F105

Check L104, L139

Check if there is any major difference referring

To Figure 4.1.1 (g). Is any signal de te ct ed at

RF signal path is OK. See next page to Rx I/Q data signal

LG Electronics Inc.

YES

Check pin3 at DP100

Replace DP100

that point?

Z3X-BOX.COM

YES

Is any signal detected at

that point?

YES

Check L117, C126, L125, C136

- 44/147 -

Page 46

CX8550

U101 pin2

Waveform

4.1.1 (e)

F105 pin6

DP100 pin3

4.1.1 (f)

Z3X-BOX.COM

LG Electronics Inc.

4.1.1 (g)

- 45/147 -

Page 47

CX8550

4.1.1.5 Checking Rx I/Q data

Test Point

U110 Pin7 (RX0_QM)

Pin8 (RX0_QP) Pin9 (RX0_IM) Pin10 (RX0_IP)

Circuit Diagram

Z3X-BOX.COM

LG Electronics Inc.

- 46/147 -

Page 48

CX8550

Start

Checking Flow

Check if there is any major difference referring

Redownload S/W, and then recalibrate the Main B/D

Check if there is any major difference referring

All DCN Rx check is completed . If the phone still do

Check pin7, 8, 9, 10 at U110

To Figure 4.1.1 (h), (i)

Check pin7, 8, 9, 10 at U110

To Figure 4.1.1 (h), (i)

not work , change Main B /D.

Waveform

YES

Replace U110

Replace Main B /D

YES

RX0_IP

RX0_IM RX_Q_

Graph 4.1.1(h)

LG Electronics Inc.

Z3X-BOX.COM

RX0_QP

RX0_Q M

RX_Q_ N

Graph 4.1.1(i)

- 47/147 -

Page 49

CX8550

4.1.2 PCS Rx

Mobile S/W

Test Point

VCTCXO

Diplexer

PCS_Duplexer

RFR6500

Start

Rx TESTSETUP(Joyphone )

- Test Channel: 675

-TestBand:USPCS

- SID: 4182

- Sector Power: -30 dBm Spectrum Analyzer Setting

Oscilloscope Setting

Z3X-BOX.COM

DC Power Supply circuit

1. Check

2. Check VCTCXO

Checking Flow

3. Check

Control signal

4. Check

RF Signal path

5. Check

Rx I/Q data

LG Electronics Inc.

Redownload S/W, Cal

- 48/147 -

Page 50

CX8550

4.1.2.1 Checking DC Power supply circuit (PMIC)

Test Point

R328

Circuit Diagram

R330

TP1

TP2

Z3X-BOX.COM

LG Electronics Inc.

- 49/147 -

Page 51

CX8550

Start

Checking Flow

Check R330

+2.9V_RX is OK?

YES

Check R328

+2.6 V_MSMP2 is OK?

YES

DC Power supplyCircuit is OK. See next Pagetocheck

VCTCXO circuit

The Problem may be Logic part

Referto Logic troubleshoot

The Problem may be Logic part

Referto Logic troubleshoot

LG Electronics Inc.

Z3X-BOX.COM

- 50/147 -

Page 52

CX8550

4.1.2.2 Checking VCTCXO circuit

Test Point

X100 pin3

X100 pin4

Circuit Diagram

TP2

TP1

Z3X-BOX.COM

LG Electronics Inc.

- 51/147 -

Page 53

CX8550

Start

Checking Flow

Check X100 pin3

Is it 19.2MHz? (Refer to

figure 4.1.1 (a))

Check X100 pin4

Is it 2.8V? (Refer to

figure 4.1.1 (b))

YES

Replace X100 and then check C152, R107.

Is it similar?

Replace Main B /D

VCTCXO circuit is Ok . See next page

YES

to check control signal .

Th e Pro ble m may be Logic par t

Refer to Logic troubleshoot

VCTCXO circuit is Ok . See next page

to check control signal .

Figure 4.1.1 (a)

LG Electronics Inc.

Waveform

Z3X-BOX.COM

Figure 4.1.1 (b)

- 52/147 -

Page 54

CX8550

4.1.2.3 Checking Control circuit

U110 pin49(SBST0)

pin50(SBDT0) pin51(SBCK0)

Test Point

Circuit Diagram

Z3X-BOX.COM

LG Electronics Inc.

- 53/147 -

Page 55

CX8550

Start

Checking Flow

Check if there is any major difference referring

Check pin49, 50, 51 at U110

To Figure 4.1.1 (c), (d)

Redownload S/W

Check pin49, 50, 51 at U110

Check if there is any major difference referring

To Figure 4.1.1 (c), (d)

Replace Main B /D

YES

Control signal is Ok . See next page

to check RF signal path .

Control signal is Ok . See next page

to check RF signal path .

Z3X-BOX.COM

Figure 4.1.1 (c)

Waveform

Figure 4.1.1 (d)

LG Electronics Inc.

- 54/147 -

Page 56

CX8550

4.1.2.4 Checking RF signal path (Mobile S/W, Diplexer, Duplexer)

Test Point

F105.

U10

1. Pin2

C103, L103

Pin4

C185, L140, L106

DP101. Pin3

C135, C127 L126, C134

TP1

Circuit Diagram

PCS Tx DCN Tx PCS Rx DCN Rx

TP2

Z3X-BOX.COM

TP3

LG Electronics Inc.

- 55/147 -

Page 57

CX8550

Start

Checking Flow

Check if there is any major difference referring

Check pin2 at U101

To Figure 4.1.1 (e). Is any signal detected at

that point?

YES

Is any signal detected at

that point?

YES

Check pin6 at F105

Check if there is any major difference referring

To Figure 4.1.1 (f). Is any signal detected at

that point?

YES

Is any signal detected at

that point?

Replace U101

Check C103, L103

Replace F105

Check L104, L139

Check if there is any major difference referring

To Figure 4.1.1 (g). Is any signal de te ct ed at

RF signal path is OK. See next page to Rx I/Q data signal

LG Electronics Inc.

YES

Check pin3 at DP101

Replace DP101

that point?

Z3X-BOX.COM

YES

Is any signal detected at

that point?

YES

Check C135, C127, L126, C134

- 56/147 -

Page 58

CX8550

U101 Pin 2

Waveform

F105 Pin 4

DP101 Pin 2

Z3X-BOX.COM

LG Electronics Inc.

- 57/147 -

Page 59

CX8550

4.1.2.5 Checking Rx I/Q data

Test Point

U110 Pin7 (RX0_QM)

Pin8 (RX0_QP) Pin9 (RX0_IM) Pin10 (RX0_IP)

Circuit Diagram

Z3X-BOX.COM

LG Electronics Inc.

- 58/147 -

Page 60

CX8550

Start

Checking Flow

Check if there is any major difference referring

Check pin7, 8, 9, 10 at U110

To Figure 4.1.1 (h), (i)

Redownload S/W, and then recalibrate the Main B/D

Check pin7, 8, 9, 10 at U110

Check if there is any major difference referring

To Figure 4.1.1 (h), (i)

All DCN Rx check is completed . If the phone still do

not work , change Main B /D.

YES

Replace U110

Replace Main B /D

YES

RX0_IP

RX0_IM RX_Q_

Graph 4.1.1(h)

LG Electronics Inc.

Waveform

Z3X-BOX.COM

RX0_QP

RX0_Q M

RX_Q_ N

Graph 4.1.1(i)

- 59/147 -

Page 61

CX8550

4.2 Tx Part Trouble

4.2.1 DCN Tx

DCN_Tx SAW filter

Mobile S/W

Dual PAM

Test Point

Diplexer

DCN_Duplexer

VCTCXO

RFT6150

Checking Flow

Start

Press “##5473784236368” + “SEND ”key + “000000” in Phone idle state. ? Press “5” to enter FCC Test ? Press “2” to enter CDMA FCC mode

- Set channel to 384 and AGC to 360

? Measure frequency domain waveform with Spectrum

analyser

? Measure time domain waveform with Oscilloscope

DC Power Supply circuit

Z3X-BOX.COM

1. Check

4. Check RF SAW

5. Check

RF Dual PAM

6. Check

Duplexer

7. Check Diplexer

LG Electronics Inc.

2. Check VCTCXO

3. Check RFT6150

8. Check

Mobile Switch

Redownload S/W, Cal

- 60/147 -

Page 62

CX8550

4.2.1.1 Checking DC Power supply circuit (PMIC)

Test Point

R328

R333

Circuit Diagram

TP1

TP2

Z3X-BOX.COM

LG Electronics Inc.

- 61/147 -

Page 63

CX8550

Start

Checking Flow

Check R333

+2.9V_TX is OK?

YES

Check R328

+2.6V_MSMP2 is OK?

YES

DC Power supply Circuit is OK. See next Pagetocheck

VCTCXO circuit

The Problem may be Logic part

Refer to Logic troubleshoot

The Problem may be Logic part

Refer to Logic troubleshoot

LG Electronics Inc.

Z3X-BOX.COM

- 62/147 -

Page 64

CX8550

4.2.1.2 Checking VCTCXO circuit

X100 pin3

Test Point

X100 pin4

Circuit Diagram

TP2

TP1

Z3X-BOX.COM

LG Electronics Inc.

- 63/147 -

Page 65

CX8550

Start

Checking Flow

Check X100 pin3

Is it 19.2MHz? (Refer to

figure 4.1.1 (a))

Check X100 pin4

Is it 2.8V? (Refer to

figure 4.1.1 (b))

YES

Replace X100 and then check C152, R107.

Is it similar?

Replace Main B /D

VCTCXO circuit is Ok . See next page

YES

to check control signal .

Th e Pro ble m may be Logic par t

Refer to Logic troubleshoot

VCTCXO circuit is Ok . See next page

to check control signal .

Figure 4.1.1 (a)

LG Electronics Inc.

Waveform

Z3X-BOX.COM

Figure 4.1.1 (b)

- 64/147 -

Page 66

CX8550

4.2.1.3 Checking RFT6150 circuit

Test Point

CELL_OUT

TX_QP TX_QM

TX_IP TX_IM

PIN23

PIN 27 PIN 28 PIN 29 PIN 30

PIN 1, 2, 3, 4

TX_ON, SBCK0, SBDT0, SBST0

Circuit Diagram

U111

PIN15

TCXO

LG Electronics Inc.

TP2

Z3X-BOX.COM

TP1

TP3

TP4

TP5

- 65/147 -

Page 67

CX8550

Start

Checking Flow

Check if there is any major difference referring

Check pin23 at U111

To Figure 4.2.1.4 (a). Is it similar?

YES

Check I/Q data at U111

Check if there is any major difference referring

To Figure 4.2.1.4 (b). Is it similar?

YES

Check pin1 at U111(TX_ON signal)

whether it is higher than 2 . 5 V.

YES

Check pin15 at U111 (TCXO signal)

referring to Figure 4.2.1.4 (b). Is it similar?

YES

RFT6150 circuit is OK. See next page

Check U204 MSM6500

Check TX_ON signal & MSM

Check TCXO circuit.

YES

Check pin2, 3, 4 at U111 referring To Figure 4.2.1.4 (d). Is it similar?

YES

Check SBI signal line & MSM

Z3X-BOX.COM

Replace U111

LG Electronics Inc.

- 66/147 -

Page 68

CX8550

Waveform

Graph 4.2.1.4(A) Graph 4.2.1.4(C)

RX_I_P

RX_I_N

SBD T

SBC K

RX_Q_P

RX_Q_N

Graph

4.2.1.4(B)

Z3X-BOX.COM

SBS T

SBC K

LG Electronics Inc.

Graph

4.2.1.4(D)

- 67/147 -

Page 69

CX8550

4.2.1.4 Check DCN RF Tx SAW

F104

RF_IN

Test Point

RF_OUT

Circuit Diagram

TP1TP2

Checking Flow

Start

Check pin1, 3

at F104. Referring to

Figure 4.2.1.5.

Is it similar?

Replace F 104

Waveform

RF_IN fed up with CW signal

RF_IN

YES

RF Tx S AW is OK

Z3X-BOX.COM

RF_OUT

LG Electronics Inc.

Figure 4.2.1.5

- 68/147 -

Page 70

CX8550

4.2.1.5 Check DCN PAM circuit

Test Point

RFOUT_CELL

RFIN_CELL VBATT

Circuit Diagram

VCCA

VMODEVEN_CELL

TP3

LG Electronics Inc.

Z3X-BOX.COM

PCS Tx DCN Tx

TP1

TP4

TP2

- 69/147 -

Page 71

CX8550

Start

Checking Flow

Check if there is any major difference referring

Check pin2, 13 at U107

To Figure 4.2.1.6. Is it similar?

YES

Check pin4, 11 at U107(Vcc)

whether it is higher than 3 .4V .

YES

Check pin3 at U107(P A_R1 signal)

whether it is lower than 2.2V.

YES

Replace U107

YES

PAM circuit is OK. See next page

Check Vcc line

Check PA_R1 line

LG Electronics Inc.

Waveform

Z3X-BOX.COM

RF_IN fed up with CW signal

in low gain mode of PAM

Waveform

RF_IN

RF_OUT

Figure 4.2.1.6

- 70/147 -

Page 72

CX8550

4.2.1.6 Check DCN Duplexer

Test Point

ANT_PORT

TX_PORT

Checking Flow

DP100

Circuit Diagram

TP2

Waveform

TP1

Start

Check pin1, 3

at DP101. Referring to

Figure 4.2.2.7.

Is it similar?

Replace DP 101

Tx Port

YES

Duplexer is

Z3X-BOX.COM

ANT Port

LG Electronics Inc.

Figure 4.2.1.7

- 71/147 -

Page 73

CX8550

4.2.1.7 Check Diplexer

Test Point

Ant Port

F105

DCN Port

Checking Flow

TP1

Circuit Diagram

PCS Tx DCN Tx PCS Rx DCN Rx

TP2

Waveform

Start

Check pin2, 4

at F105. Referring to

Figure 4.2.2.8.

Is it similar?

Replace F 105

DCN Port

YES

Diplexer is

Z3X-BOX.COM

ANT Port

LG Electronics Inc.

- 72/147 -

Page 74

CX8550

4.2.1.8 Check Mobile S/W

Test Point

RF OUT

RF IN

Checking Flow

Circuit Diagram

TP2

Waveform

TP1

Start

Check pin1, 2

at U101. Referring to

Figure 4.2.1.9.

Is it similar?

Replace F 105

RF IN

Mobile S /W is

YES

Z3X-BOX.COM

RF OUT

LG Electronics Inc.

Figure 4.2.1.9

- 73/147 -

Page 75

CX8550

4.2.2 PCS Tx

Mobile S/W

PCS_Tx SAW filter

RFT6150

Dual PAM

VCTCXO

Test Point

Diplexer

PCS Duplexer

Circuit Diagram

Start

Press “##5473784236368” + “SEND ”key + “000000” in Phone idle state. ? Press “5” to enter FCC Test ? Press “2” to enter PCS FCC mode

- Set channel to 600 and AGC to 360

? Measure frequency domain waveform with Spectrum

analyser

? Measure time domain waveform with Oscilloscope

Z3X-BOX.COM

DC Power Supply circuit

1. Check

4. Check RF SAW

5. Check

RF Dual PAM

6. Check

Duplexer

7. Check Diplexer

LG Electronics Inc.

2. Check VCTCXO

3. Check RFT6150

8. Check

Mobile Switch

Redownload S/W, Cal

- 74/147 -

Page 76

CX8550

4.2.2.1 Checking DC Power supply circuit (PMIC)

Test Point

R328

R333

Circuit Diagram

TP1

TP2

Z3X-BOX.COM

LG Electronics Inc.

- 75/147 -

Page 77

CX8550

Start

Checking Flow

Check R333

+2.9V_TX is OK?

YES

Check R328

+2.6 V_MSMP2 is OK?

YES

DC Power supplyCircuit is OK. See next Pagetocheck

VCTCXO circuit

The Problem may be Logic part

Referto Logic troubleshoot

The Problem may be Logic part

Referto Logic troubleshoot

LG Electronics Inc.

Z3X-BOX.COM

- 76/147 -

Page 78

CX8550

4.2.2.2 Checking VCTCXO circuit

X100 pin3

Test Point

X100 pin4

Circuit Diagram

TP2

TP1

Z3X-BOX.COM

LG Electronics Inc.

- 77/147 -

Page 79

CX8550

Start

Checking Flow

Check X100 pin3

Is it 19.2MHz? (Refer to

figure 4.1.1 (a))

Check X100 pin4

Is it 2.8V? (Refer to

figure 4.1.1 (b))

YES

Replace X100 and then check C152, R107.

Is it similar?

Replace Main B /D

VCTCXO circuit is Ok . See next page

YES

to check control signal .

Th e Pro ble m may be Logic par t

Refer to Logic troubleshoot

VCTCXO circuit is Ok . See next page

to check control signal .

Figure 4.1.1 (a)

LG Electronics Inc.

Waveform

Z3X-BOX.COM

Figure 4.1.1 (b)

- 78/147 -

Page 80

CX8550

4.2.2.3 Checking RFT6150 circuit

TX_QP TX_QM

TX_IP TX_IM

Test Point

PIN21

PIN 27 PIN 28 PIN 29 PIN 30

PIN 1, 2, 3, 4

PCS_OUT

PIN15

TCXO

U111

TX_ON, SBCK0, SBDT0, SBST0

Circuit Diagram

TP1

TP2

Z3X-BOX.COM

LG Electronics Inc.

TP3

TP4

TP5

- 79/147 -

Page 81

CX8550

Start

Checking Flow

Check if there is any major difference referring

Check pin21 at U111

To Figure 4.2.2.4 (a). Is it similar?

YES

Check I/Q data at U111

Check if there is any major difference referring

To Figure 4.2.2.4 (b). Is it similar?

YES

Check pin1 at U111(TX_ON signal)

whether it is higher than 2 . 5V.

YES

Check pin15 at U111 (TCXO signal)

referring to Figure 4.2.2.4 (b). Is it similar?

YES

RFT6150 circuit is OK. See next page

Check U204 MSM6500

Check TX_ON signal & MSM

Check TCXO circuit.

YES

Check pin2, 3, 4 at U111 referring To Figure 4.2.2.4 (d). Is it similar?

YES

Z3X-BOX.COM

Replace U111

Check SBI signal line & MSM

LG Electronics Inc.

- 80/147 -

Page 82

CX8550

Waveform

Graph 4.2.2.4(A) Graph 4.2.2.4(C)

RX_I_P

RX_I_N

SBD T

SBC K

RX_Q_P

RX_Q_N

Graph

4.2.2.4(B)

Z3X-BOX.COM

SBS T

SBC K

LG Electronics Inc.

Graph

4.2.2.4(D)

- 81/147 -

Page 83

CX8550

4.2.2.4 Check DCN RF Tx SAW

Test Point

RF_OUT

F103

RF_IN

Checking Flow

Circuit Diagram

Waveform

TP1TP2

Start

Check pin1, 4

at F103. Referring to

Figure 4.2.2.5.

Is it similar?

Replace F 103

RF_IN fed up with CW signal

RF Tx SAW is

YES

RF_IN

Z3X-BOX.COM

RF_OUT

LG Electronics Inc.

Figure 4.2.2.5

- 82/147 -

Page 84

CX8550

4.2.2.5 Check DCN PAM circuit

Test Point

VMODE

VCC

VBATT

RFIN_PCS

Circuit Diagram

RFOUT_PCS

VEN_PCS

TP3

LG Electronics Inc.

TP2

TP1

Z3X-BOX.COM

PCS Tx DCN Tx

TP4

- 83/147 -

Page 85

CX8550

Start

Checking Flow

Check if there is any major difference referring

Check pin6, 8 at U107

To Figure 4.2.2.6. Is it similar?

YES

Check pin4, 12 at U107(Vcc)

whether it is higher than 3 .4V .

YES

Check pin7 at U107(P A_R1 signal)

whether it is higher than 2 . 2V.

YES

Check pin3 at U107(P A_R1 signal)

whether it is lower than 2.2V.

YES

PAM circuit is OK. See next page

Check Vcc line

Check PA_ON line

Check PA_R1 line

YES

Replace U107

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RF_IN fed up with CW signal

in low gain mode of PAM

Waveform

Figure 4.2.2.6

RF_OUT

LG Electronics Inc.

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Page 86

CX8550

4.2.2.6 Check PCS Duplexer

Test Point

ANT_PORT

TX_PORT

Checking Flow

DP101

Circuit Diagram

TP2

Waveform

TP1

Start

Check pin1, 3

at DP101. Referring to

Figure 4.2.2.7.

Is it similar?

Replace DP 101

Tx Port

YES

Duplexer is

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ANT Port

LG Electronics Inc.

Figure 4.2.2.7

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Page 87

CX8550

4.2.2.7 Check Diplexer

Test Point

Ant Port

F105

PCS Port

Checking Flow

TP1

Circuit Diagram

PCS Tx DCN Tx PCS Rx DCN Rx

TP2

Waveform

Start

Check pin2, 6

at F105. Referring to

Figure 4.2.1.8.

Is it similar?

Replace F 105

Diplexer is OK

YES

PCS Port

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ANT Port

LG Electronics Inc.

Figure 4.2.2.8

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Page 88

CX8550

4.2.2.8 Check Mobile S/W

Test Point

RF OUT

RF IN

Checking Flow

Circuit Diagram

TP2

Waveform

TP1

Start

Check pin1, 2

at U101. Referring to

Figure 4.2.1.9.

Is it similar?

Replace F 105

RF IN

Mobile S /W is

YES

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RF OUT

LG Electronics Inc.

Figure 4.2.2.9

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Page 89

CX8550

4.3 Logic Part Trouble

4.3.1 Power

4.3.1.1 Power-On Trouble

Circuit Diagram

+1.4_MSMC

+1.8_MSMP1

L301

L302

Test point

R328

+1.8V_MSMP1

+2.6V_MSMP2

R330

+2.9V_RX

R331

+2.6V_MSMA

R332

+2.8V_TCXO

+1.4V_MSMC

+2.6V_MSMP2

U303

LG Electronics Inc.

+2.8V_TCXO

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+2.9V_RX

+2.6V_MSMA

- 88/147 -

Page 90

CX8550

START

Checking Flow

Check battery voltage > 3.4V

YES

Push power-on key and

check the level change of U303

PWR_ON

YES

Check the voltage of

the following port at U303

+1.4V_MSMC +1.8V_MSMP1 +2.6V_MSMP2

+2.6V_MSMA

+2.8V_TCXO

YES

Logic level at PS_HOLD(R306)

of U303=High ?

YES

Charge of Change Battery and try again

Check the contact of power-key

Replace U303

Re-download software

andtry again

YES

Does it work properly?

The Phone will power on

LG Electronics Inc.

YES

Does it work properly?

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Re-download software

andtry again

Re-download software

andtry again

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Page 91

CX8550

4.3.1.1 Charging Trouble

Circuit Diagram

+5V_CHAR +5V_USB

Circuit Diagram

Battery Vcc

+VPWR

Test point

Pin1 CON 701

U306

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U702

+5V_USB of D301 pin2

+5V_CHAR of D301 pin1

LG Electronics Inc.

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Page 92

CX8550

START

Checking Flow

Charging Connector CON400

Well-soldered?

YES

Voltage at Pin1, Pin2

of D301 = 5V?

YES

0.1V < Voltage of CHAR_MON< 1.22V

YES

Voltageof pin 1 CON701 =

VBATT(+VPWR)

YES

Is the battery charged?

The charging adaptor (TA) or USB c abl e(USB port

NO NO

Re-soldering CON400

of computer) is out of order.

Replace U306

Check the soldering

YES

Replace U702 Re-solder U702

The battery may have the problem.

Change the battery and try again.

Charging will operate properly

LG Electronics Inc.

YES

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Page 93

CX8550

4.3.2 DSP

4.3.2.1 DSP Trouble

R700

Clock out

–28MHz

Circuit Diagram

C702

DSP_RESET/

TP700 TP701 TP702 TP703 TP704

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TP705

LG Electronics Inc.

- 92/147 -

Page 94

CX8550

R324

+2.6V_DSP_IO2

R325

+1.8V_DSP_IO1

R326

+1.2V_DSP_CORE1

R321

+1.2V_DSP_IO2

TP704 TP703

TP701 TP702

TP700 TP705

R700

LG Electronics Inc.

Test point

C702

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Page 95

CX8550

START

Checking Flow

Check the voltage of the following LDOs

+1.2V_DSP_CORE1, +1.2V_DSP_CORE2,

+1.8V_DS P_IO1 +2.6V_DS P_IO2

YES

Check DSP Clock at R700

YES

Check the control signal

TP700 ~TP705 & C702

YES

DSP will operate properly

Replace U307, U308, U309, U310

Replace X700

Replace U701

LG Electronics Inc.

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Page 96

CX8550

4.3.3 LCD

4.3.3.1 LCD Trouble

Check point

- The assembly status of the LCD Module

- The assembly status of the main connector

- The Soldering of connector

F206 F208

Circuit Diagram

F209

F205

LCD Control signals

From DSP : LCD_D[0:15], LCD_CS/, LCD_WE, LCD_ID, From MSM : LCD_RESET/,

F208

F207

Test point

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F209

F206 F205

LG Electronics Inc.

- 95/147 -

Page 97

CX8550

START

Checking Flow

Does LCDwor k pr o pe r ly

YES

Check the DSPTrouble (4.3.2)

YES

Check theVoltageof R329 =2.8V?

YES

Checkthe Control signal Data[0:15]

LCD_RESET/, LCD_CS / , WE/

YES

ChangetheLCDModule

Replace U701

Replace U303

Check F205, F206, F20 7, F208 , F209 (Signal line)

Che ck CON202soldering

LCDdis p l aywill w ork pr operly

LG Electronics Inc.

YES

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Re-solderCON202

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Page 98

CX8550

4.3.4 Camera

4.3.4.1 Camera Trouble

Circuit Diagram

R106 CAM_SCL R107 CAM_SDA

C113 CAM_MCLK

C100

+1.8V_C

AM_D

C101

+2.6V_C

AM_IO

F100

C108

F101

CAM_PCLK

C107

CAM_RESET/

C113

Test point

C110C109

C107

C108

+2.8V_CA

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C102

M_A

LG Electronics Inc.

U105

U106

U104

- 97/147 -

Page 99

CX8550

START

Checking Flow

Check the DSP Trouble

YES

Check the clock from Camera

at C108; CAM_PCLK

YES

Check the Voltage of

the following LDOs: +1.8V_CAM_D,

+2 .6 V_CAM_IO, +2.8V_CAM_A

YES

Check the Control signal

CAM_DATA[0:7], CAM_RESET/,

CAM_SDA, CAM_SCL

Replace U701 or Main board

Replace the Camera module

Replace U104, U105, U106

Check F100, F101, C107, C 108, C109, C110,

C113(Signal line),

LG Electronics Inc.

YES

Check CON100 Soldering

YES

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Camera will work properly

Re-solder CON100

- 98/147 -

Page 100

CX8550

4.3.5 Audio

4.3.5.1 Speaker Trouble

Circuit Diagram

R533 +2.8V_TCXO

CODEC part

+1.8V_MSMP1

MIC Analog S/W part

R532

R525 Level

translated clock

C519 HPH_L

C520 HPH_R

R530

+3.0V_DSP_SD

R532 +VPWR

Headset Amp. part

LG Electronics Inc.

Z3X-BOX.COM

- 99/147 -

LG CX8550 Service Manual

Specifications and Main Features

Frequently Asked Questions

User Manual