LG LG-YD636 User manual

CDMA MOBILE SUBSCRIBER UNIT
LG-YD636
SINGLE BAND
CDMA MOBILE PHONE
SERVICE MANUAL

Table of Contents
CHAPTER 1. NAM Input Method(Inputting of telephone numbers included)
1. Telephone Number and NAM Programming Method
CHAPTER 2. Circuit Description
1. RF Transmit/Receive Part
2. Digital/Voice Processing Part
CHAPTER 3. Trouble Shooting
CHAPTER 4. Safety

CHAPTER 1. NAM Input Method
(Inputting of telephone numbers included)
1. HOW TO POWER UP
ENTER PIN
Avail Cnt: 03
[ ]
ENTER PIN
Avail Cnt: 03
[**** ]
CHV PIN
Verified
1. When you press power key, “Enter PIN Avail cnt:03” message is displayed.
2. You have to input correct PIN code[Default Code: 1234], then press [OK] key.
3. Handset start data loading process, and then searching signal.
2. NAM Input Method
(Inputting of telephone numbers included)
1. Telephone Number and NAM Programming Method
•Press “ ******159753 ” in idle state
Then, the following Menu is appeared.
1 . Service Menu
2 . Test Screen
3 . Test Call
4 . Vocoder Set
5 . Verify ADM
6 . Error Screen
7 . Del Error
SlotCycle Idx
Phone Model
•Press 1to program the telephone number and NAM.
•Phone model displayed , then press [OK].
•Slot cycle index displayed , then press [OK].
Phone Number
Nam Name
ACCOLC
•Phone number displayed , then press [OK].

•Nam Name is displayed , then press [OK].
•ACCOLC is displayed, then press[OK].
•Now, the basic programming is completed. To reset the handset, press [ Done].
The detail programming method is same as basic programming. Set up required values and then,
press the Up-Down key in an effort to move to the next screen..
The editable NAM items are followed:
SERVICE RPOGRAMMING CODE
NAM1 MOBILE COUNTRY CODE
NAM 1 MOBILE NETWORK CODE
NAM 1 PRL Enabled
NAM 1 CDMA Home System Reg
NAM 1 CDMA Foreign SID Reg
NAM 1 CDMA Foreign NID Reg
NAM 1 CDMA Home SID/NID
NAM 1 Lock out SID/NID
NAM1 CDMA Primary CH A
NAM1 CDMA Primary CH B
NAM1 CDMA Secondary CH A
NAM1 CDMA Secondary CH B
Editing this items is not recommended.※
3. FCC TEST MENU
1. FCC TEST MENU: Press ******159753 in idle state Left/Right Key in an effort to move
to the DEBUG MENU2 Select CDMA FCC
2. Channel setting: input channel number
3. Power setting: input power number ( Input Power Setting 0~511, Normal Input is CH 400)
4. If you want to end the test, press END Key, then handset will be reset.
Input Channel
Input Power

1. RF Transmit/Receive Part
1.1 Overview
The Tx and Rx part employs the Direct-Conversion system. The Tx and Rx frequencies are
824.04~848.97 and 869.04~893.97. RF signals received through the antenna are seperated by the
duplexer.
RF Signal fed into the RFR6122(RF receiver ) through the duplexer. The IF 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) 6025
processes the data from ADC. The digital processing part is a demodulator.
In the case of transmission, RFT6122 receives OQPSK-modulated anlaog signal from the MSM6025.
The RFT6122 connects directly with MSM6025 using an analog baseband interface. In RFT6122, 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.
1.2 Description of Receive Part Circuit
1.2.1 Duplexer ( EFSD836MD2S2 )
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 LG-YD636 duplexer described below ;
Tx Rx Tx to Rx (min)
Pass Band 824~849MHz 869~894 MHz
Insertion Loss 2.0dB max 4.0dB max
VSWR 2.2 max 2.2 max
Attenuation 45.0dB min (869~894MHz) 55.0dBmin(824~849MHz) 55.0dB (824~849MHz)
45.0dB (869~894MHz)
CHAPTER 2. Circuit Description

1.2.2 Receiver ( RFR6122 )
The RFR6122 is RF RECEIVER ( LNA&MIXER, ADC CONVERTER) 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 LG-YD636 LNA is described below:
Gain mode 0 Gain mode 1 Gain mode 2 Gain mode 3 Units
Parameter
Cellular Cellular Cellular Cellular
Gain 16.3 4.0 -4.4 -18.0 dB
Noise Figure 1.60 5.0 5.0 20.0 dB
Input IP3 16.5 8.7 15.0 15.0 dBm
The RFR6122 IC is an RF-to-baseband receiver IC and provides the Zero-IF receiver signal path for
Cellular-CDMA reception. For this chipset, Cellular-CDMA refers to band classes 0 and 3 as defined
by the cdma2000 standard, with mobile station receivers operating between 824 and 894 MHz. The
Rx signal path includes the LNA, quadrature downconversion, and baseband functions.
Numerous secondary functions are integrated on-chip: the Rx LO generation and distribution circuits,
the UHF VCO circuits, and various interface, control, and status circuits.
The Cellular-CDMA receive signal is routed from the antenna to the RFR6122 IC via the duplexer. The
analog baseband outputs interface with one of MSM6025 devices that also provide status and control
signaling. Power reduction features controlled by the MSM6025 device (such as selective circuit
power-down, gain control, and bias control) extend handset standby time. Integrated Rx LO circuits,
ideally supplemented by the RFT6122 transmitter IC.
1.2.3 Receive RF SAW Filter
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.
RX RF filter has IL of 2.2dB (Max) on the average whereas the ripple of passband is about 1.0dB
(Max) and the RF signal suppression rate on transmit band is 47dB (Min).

1.3 Transmit Part Circuit Description
1.3.1 RFT6122
The RFT6122 baseband-to-RF Transmit Processor performs all Tx signal-processing functions
required between digital baseband and the Power Amplifier Modulator (PAM). The baseband
quadrature signals are upconverted to the Cellular frequency bands and amplified to provide signal
drive capability to the PAM. The RFT6122 includes an mixers for up-converting analog baseband to
RF, a programmable PLL for generating Tx and Rx LO frequency, cellular driver amplifiers and Tx
power control through an 85 dB VGA. As added benefit, the single sideband upconversion eliminates
the need for a band pass filter normally required between the upconverter and driver amplifier. I, I/,
Q and Q/ signals proceed from the MSM6025 to RFT6122 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 RFT6122 converts baseband signals into RF signals.
After passing through the upconverters, RF signal is inputted into the Power AMP.
 RFT6122 Cellular CDMA RF Specifications
Parameter Condition Min. Typ. Max. Units
Rated Output Power Average CDMA Cellular 6.0 dBm
Min Output Power Average CDMA Cellular -75 dBm
Rx band noise power CDMA Cellular -132 dBm/Hz
ACPR Cellular: Fc±885kHz -52 dBc/
1.3.2 Power Amplifier
The power amplifier that can be used in the CDMA mode has linear amplification capability.
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 through 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 +17dBm and conversion gain is
about 28dB in the CDMA mode.

1.4 Description of Frequency Synthesizer Circuit
1.4.1 Voltage Control Temperature Compensation Crystal Oscillator
The temperature range that can be compensated by VC-TCXO which is the reference frequency
generator of a mobile station is -30~+80 C.
The VC-TCXO receives frequency tuning signals called TRK_LO_ADJ from MSM as 0.5V~2.5V DC
via R and C filters in order to generate the reference frequency of 19.2MHz and input it into the
frequency synthesizer of UHF band. Frequency stability depending on temperature is ±2.0 ppm.
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 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 MSM6025. 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 MSM6025, and amplifying part that amplifies signals coming out from MIC and transferring them
to the audio processor.

2.2.3 MSM6025 (Mobile Station Modem) 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 flash memory, SDRAM for storing data.
2.2.5 Power Supply Part
The PMIC(PM6610) is made up of 7 Regulators and direct connet to Batt.
Regulator(150mA )s give the power each Circuits(RFR,RFT, MSMA,MSMP,MSMC,RUIM).
Regulator(50mA) gives the power to the TCXO parts.
PAM, Motor, LED, Charge Pump and Audio amplifier are directly conneted to Battery.
2.3 Circuit Description
2.3.1 Keypad/LCD and Receptacle Part
Once the keypad is pressed, the key signals are sent out to MSM6100 for processing. In addition,
when the key is pressed, the keypad/LCD lights up through the use of 16 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 MSM6025) 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 MSM6025 activate the ringer by using signals generated in the timer
in MSM6025.
2.3.3 MSM Part
The MSM6025 chipset integrates functions that support both tri-mode CDMA/FM and cellular-only
handset operation. Subsystems within the MSM6025 baseband processor device include a CDMA

processor, digital FM (DFM) processor, QCT’s latest generation of DSP, the QDSP4000™ core, for
voice compression and applications support, PLL and an ARM® ARM7TDMI microprocessor. Also
integrated in the MSM6025 device are analog functions such as a wideband mono codec and analog
interfaces for the radioOne RF ASICs. Controllers for a universal serial bus (USB), device controller
for an R-UIM (CDMA SIM), GPIOs, and peripheral interfaces complete the system integration. And the
MSM6025 chipset and system software are designed to support IS95A/95B and Release 0 of
CDMA2000 standards.
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.
2.3.4 Memory Part
Memory part consists of 64 Mbits Flash Memory and 32 Mbits Static RAM. the Flash Memory part are
programs used for terminal operation. The programs can be changed through down loading after the
assembling of terminals. On the SRAM data generated during the terminal operation are stored
temporarily.
2.3.5 UIM Part
The MSM6025 is supports RUIM.
The UIM card contains the informations of phone number, PIM data, SMS data, etc.
The whole circuits are designed to operate 2.85V UIM cards.
2.3.6 Power Supply Part
Turn On
When the battery voltage (4.2V ~ 3.2V) is fed and the PWR key of keypad is pressed, PMIC is
activated by the PWR_ON_SW/ signal, and then the control signal PS_HOLD signal is generated.
And then, the regurator 1.9V_MSMC & 2.85V_MSMP, 2.6V_MSMA, are operated.
Operating
During the phone is on operating state,
LDO(in PMIC) for MSM is always enable and gives the power MSM6025 and memory part

LDO(in PMIC) for +2.60V_TX part is enabled on traffic state, and gives the power TX part devices.
LDO(in PMIC) for +2.60V_RX part is enabled on idel state, and gives the power RX part devices.
Turn OFF
When the PWR key is pressed during a few seconds, PMIC is turned on by PWR_ON_SW/ and
then, 'Low' is outputted on PS_HOLD. MSM6025 receives this signal and then, recognizes that the
POWER key has been pressed. During this time, MSM6025 outputs PS_HOLD as low and turn off
all devices
2.3.7 Logic Part
The Logic part consists of internal CPU of MSM6025, MCP(SRAM& FLASH MEMORY) .
The MSM6025 receives TCXO (=19.2MHz) from U101 and controls the phone in both CDMA and FM
modes. The major components are as follows:
CPU : ARM7TDMI microprocessor core
MEMORY :
•FLASH Memory + SRAM : 64M bits(Flash) + 32M bits(SRAM)
CPU
ARM7TDMI 32-bit microprocessor is used and CPU controls all the circuitry. Some of the features of
the ARM microprocessor include a 3 stage pipelined RISC architecture, both 32-bit ARM and 16bit
THUMB instruction setsm, a 32-bit address bus, and a 32-bit internal data bus.
FLASH Memory
Flash Memory is used to store the program of the mobile station. Using the down-loading program,
the program can be changed even after the mobile station is fully assembled.
SRAM
SRAM is used to store the internal flag information, call processing data, and timer data.
KEYPAD
For key recognition, key matrix is setup using KEY_SENSE0/-3/ signals and GPIO57-61, GPIO21 of
output ports of MSM. Backlight circuitry are included in the keypad for easy operation in the dark.
LCD MODULE
LCD module contains a controller which will display the information onto the LCD by 16-bit data from
the MSM6025. It is consist of one LCD with 128(W) X 128(H) dots 65,000 STN Color.
It is also supplied stable +2.85V_MSMP by PMIC for fine view angle and LCD reflects to improve
the display efficiency. White LEDs are used to display LCD backlight.

START
Rx TEST SETUP(HHP)
- Test Channel : 610
E5515C Setup
- CH : 610
- Sector Power : -30 dBm
Spectrum Analyzer Settiing
Oscilloscope Setting
1. Check
PMIC Circuit
2. Check
VCTCXO Circuit
3. Check
Control Signal
4. Check
Duplexer, Mobile SW
5. Check
Rx I/Q data
Redownload SW, CAL
3.1.1 When Tx power isn’t enough
Checking Flow
Test Point 1
2
3
4
5
3.1 Rx Part Trouble
CHAPTER34. Trouble Shooting
CHAPTER 3. Trouble Shooting

3.1.2 Checking Regulator Circuit
Circuit Diagram
Test Point
Checking Flow
Check Pin 29
of U401
Check Pin 7
of U401
+2.6V_Rx OK? No Pin 7. High? No Changing Board
PMIC Circuit is OK See
next Page to check
VCTCXO
Replace U401
U401. 29 (+2.6V_Rx)
U401. 7 High

3.1.3 Checking VCTCXO Circuit
Circuit Diagram
Test Point Checking Flow
Check U101 Pin 3
◆Refer to Graph 3-1(a)
Check U101 Pin 4
◆ Refer to Graph 3-1(b)
19.2MHz OK?
+2.85V OK?
No
Yes VCTCXO Circuit is Ok
See next Page to check
Duplexer
Check U401
No
Yes Changing U101
U101. 3
U101. 4
Waveform
Graph 3-1(a) Graph 3-1(b)

3.1.4 Checking Control Signal
Test Point
Checking Flow
Waveform
U107. 3 (SBDT)
U107. 4 (SBCK)
U107. 5 (SBST)
Check Pin 3, 4, 5
◆Refer to Graph 3-2(a,b)
Check SBDT, SBCK SBST
Check if there is
Any Major Difference
◆ Refer to Graph 3-2(a,b)
Level is High?
Similar?
Yes
No
Yes
No
Download the SW
Download the SW
Control Signal is Ok
See next Page to Check
Duplexer
SBDT
SBCK SBCK
SBST
Graph 3-2(a) Graph 3-2(b)

3.1.5 Checking Duplexer & Mobile SW
Test Point
Circuit Diagram
U100. 1
DP100. 8
DP100. 5

3.1.6 Checking Mobile SW & Duplexer
Checking Flow
Waveform
Check U100 Pin 1
Check if there is
Any Major Difference
◆ Refer to Graph 3-3(a)
Check DP100 Pin 8
Check if there is
Any Major Difference
◆ Refer to Graph 3-3(b)
Check DP100 Pin 5
Check if there is
Any Major Difference
◆ Refer to Graph 3-3(c)
Detected Signal?
Yes
No Changing U100
Duplexer is Ok
See next Page to check
Rx I/Q data Signal
Detected Signal?
Detected Signal?
Yes
No
No
Check C101
Changing DP100
Yes
Rx TEST SETUP(HHP)
- Test Channel : 610
E5515C Setup
- CH : 610
- Sector Power : -30 dBm
Spectrum Analyzer Settiing
Oscilloscope Setting
U100 Pin 1
Graph 3-3(a)

DP100 Pin 8
DP100 Pin 5
Graph 3-3(b)
Graph 3-3(c)

3.1.7 Checking Rx I/Q data
Test Point
Waveform
R138 (Rx_Q_P)
R137 (Rx_Q_N)
R136 (Rx_I_N)
R135 (Rx_I_P)
R135 (Rx_I_P)
R138 (Rx_Q_P)
R136(Rx_I_N)
R137(Rx_Q_N)
Checking Flow
Check R138, R137, R136, R135
Check if there is
Any Major Difference
◆Refer to Graph 3-4(a,b)
Similar?
Yes
No Replace U107
Redownload the
Software Calibrate
Graph 4-4(a) Graph 4-4(b)
Graph 3-4(a)
Graph 3-4(b)

3.2 Tx Trouble
Test Point
Checking Flow
START
√Press “******159753“ in Phone idle state
√Press right key insert FCC Mode
-Set CH400 & AGC 400
√Spectrum analyzer setting
√Oscilloscope setting
1. Check
Regulator Circuit
2. Check
VCTCXO Circuit
3. Check
SBI Control Signal
4. Check
RFT6122 Circuit
5. Check
PAM Control Signal
6. Check
Duplexer & Mobile SW
√Redownload SW, CAL
RFT6122
PAM
DUPLEXER VCTCXO
Mobile SW