Lg Lg-a270 User manual

Internal Use Only

Service Manual

LG-A270

Date: April, 2012 / Issue 1.0

Only for training and service purposes

LGE Internal Use Only

Table Of Contents

1. INTRODUCTION..................................................................... 3

1.1 Purpose ........................................................................................................3

1.2 Regulatory Information.........................................................................3

1.3 Abbreviations.............................................................................................5

2. SYSTEM SPECIFICATION ....................................................... 7

2.1 H/W Features..............................................................................................7

2.2 Technical Specication...........................................................................9

3. TECHNICAL BRIEF................................................................ 14

3.1 Digital Main Processor......................................................................... 14

3.2 Power Management ............................................................................ 17

3.3 FEM with integrated Power Amplier Module

(SKY77550, U300).................................................................................. 22

3.4 Crystal(26 MHz, X100) ......................................................................... 24

3.5 RFSYS of MT6251 (U100).................................................................... 25

3.6 MEMORY(FM25Q32, U101) ............................................................... 27

3.7 SIM Card Interface................................................................................. 29

3.8 Display Interface.................................................................................... 30

3.9 Battery Charger Interface................................................................... 32

3.10 Keypad Interface................................................................................. 33

3.11 Audio Front-End.................................................................................. 35

3.12 KEY BACLKLIGHT LED Interface .................................................... 38

3.13 Vibrator Interface................................................................................ 39

3.14 Torch LED Interface............................................................................ 40

3.15 Micro SD Card Interface ................................................................... 41

4. TROUBLE SHOOTING .......................................................... 42

4.1 RF Component ....................................................................................... 42

4.2 RX Trouble ................................................................................................ 43

4.3 TX Trouble................................................................................................. 47

4.4 FM Radio Trouble (Wired 3.5 phi/wireless) ................................. 51

4.5 Power On Trouble.................................................................................. 53

4.6 Charging Trouble................................................................................... 56

4.7 Vibrator Trouble ..................................................................................... 58

4.8 LCD Trouble ............................................................................................. 60

4.9 Speaker Trouble ..................................................................................... 62

4.10 Earphone Trouble ............................................................................... 65

4.11 Microphone Trouble.......................................................................... 68

4.12 SIM Card Interface Trouble.............................................................. 70

4.13 KEY backlight Trouble ...................................................................... 72

4.14 Torch Light Trouble ........................................................................... 74

4.15 Micro SD Trouble ................................................................................ 76

5. DOWNLOAD......................................................................... 78

6. BLOCK DIAGRAM................................................................. 91

7. CIRCUIT DIAGRAM .............................................................. 92

8. BGA PIN MAP ...................................................................... 96

9. PCB LAYOUT......................................................................... 97

10. ENGINEERING MODE ........................................................ 99

11.AUTO CALIBRATION.........................................................100

11.1 Overview..............................................................................................100

11.2 Directory structure of Tachyon....................................................100

11.3 Description of Folder & File...........................................................101

11.4 How to use Tachyon.........................................................................102

11.5 Target Power.......................................................................................105

12. EXPLODED VIEW & REPLACEMENT PART LIST .............106

12.1 EXPLODED VIEW................................................................................106

12.2 Replacement Parts ...........................................................................107

12.3 Accessory .............................................................................................119

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1. INTRODUCTION

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LGE Internal Use Only 0

1.1 Purpose

This manual provides the information necessary to repair, calibration, description and download the features of

this model.

1.2 Regulatory Information

A. Security

Toll fraud, the unauthorized use of telecommunications system by an unauthorized part (for example, persons

other than your company’s employees, agents, subcontractors, or person working on your company’s behalf)

can result in substantial additional charges for your telecommunications services. System users are responsible

for the security of own system. There are may be risks of toll fraud associated with your telecommunications

system. System users are responsible for programming and configuring the equipment to prevent unauthorized

use. The manufacturer does not warrant that this product is immune from the above case but will prevent

unauthorized use of common-carrier telecommunication service of facilities accessed through or connected to

it. The manufacturer will not be responsible for any charges that result from such unauthorized use.

B.Incidence of Harm

If a telephone company determines that the equipment provided to customer is faulty and possibly causing

harm or interruption in service to the telephone network, it should disconnect telephone service until repair can

be done. A telephone company may temporarily disconnect service as long as repair is not done.

C.Changes in Service

A local telephone company may make changes in its communications facilities or procedure. If these changes

could reasonably be expected to affect the use of the this phone or compatibility with the network, the

telephone company is required to give advanced written notice to the user, allowing the user to take

appropriate steps to maintain telephone service.

D. Maintenance Limitations

Maintenance limitations on this model must be performed only by the manufacturer or its authorized agent.

The user may not make any changes and/or repairs expect as specifically noted in this manual. Therefore, note

that unauthorized alternations or repair may affect the regulatory status of the system and may void any

remaining warranty.

1. INTRODUCTION

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1. INTRODUCTION

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E.Notice of Radiated Emissions

This model complies with rules regarding radiation and radio frequency emission as defined by local

regulatory agencies. In accordance with these agencies, you may be required to provide information such as

the following to the end user.

F. Pictures

The pictures in this manual are for illustrative purposes only; your actual hardware may look slightly different.

G. Interference and Attenuation

Phone may interfere with sensitive laboratory equipment, medical equipment, etc.Interference from

unsuppressed engines or electric motors may cause problems.

H.Electrostatic Sensitive Devices

ATTENTION

Boards, which contain Electrostatic Sensitive Device (ESD), are indicated

bythe sign. Following information is ESD handling:

rService personnel should ground themselves by using a wrist strap when exchange system

boards.

rWhen repairs are made to a system board, they should spread the floor with anti-static mat

which is also grounded.

rUse a suitable, grounded soldering iron.

rKeep sensitive parts in these protective packages until these are used.

rWhen returning system boards or parts like EEPROM to the factory, use the protective

package as described.

1. INTRODUCTION

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1. INTRODUCTION

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1.3 Abbreviations

For the purposes of this manual, following abbreviations apply:

Offset Phase Locked LoopOPLL

Light Emitting DiodeLED

Low Drop OutputLDO

Liquid Crystal DisplayLCD

Intermediate FrequencyIF

International Portable User IdentityIPUI

Global System for Mobile CommunicationsGSM

General Purpose Interface BusGPIB

Gaussian Minimum Shift KeyingGMSK

Flexible Printed Circuit BoardFPCB

Electrostatic DischargeESD

Electrical Erasable Programmable Read-Only MemoryEEPROM

Digital Signal ProcessingDSP

dB relative to 1 milli wattdBm

Digital Communication SystemDCS

Digital to Analog ConverterDAC

Constant Current – Constant VoltageCC-CV

Bit Error RatioBER

BasebandBB

Automatic Power ControlAPC

1. INTRODUCTION

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1. INTRODUCTION

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Wireless Application Protocol

WAP

Voltage Control Temperature Compensated Crystal OscillatorVCTCXO

Voltage Controlled OscillatorVCO

Universal Asynchronous Receiver/TransmitterUART

Time Division Multiple AccessTDMA

Time Division DuplexTDD

Travel AdapterTA

Side Tone Masking RatingSTMR

Pseudo SRAMPSRAM

Static Random Access MemorySRAM

Sending Loudness RatingSLR

Subscriber Identity ModuleSIM

Surface Acoustic WaveSAW

Real Time ClockRTC

Root Mean SquareRMS

Receiving Loudness RatingRLR

Radio FrequencyRF

Public Switched Telephone NetworkPSTN

Phase Locked LoopPLL

Programmable Gain AmplifierPGA

Printed Circuit BoardPCB

Power Amplifier ModulePAM

1. INTRODUCTION

2. SYSTEM SPECIFICATION

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2. SYSTEM SPECIFICATION

2.1 H/W Features

Item Feature Comment

Standard Battery Lithium-ion , 3.7V 950mAh

Stand by TIME Up to 950 hrs : Paging Period 9, RSSI 85dBm

Talk time Up to 8 hrs : GSM Tx Level 10

Charging time Approx. 3.5 hours

RX Sensitivity GSM, EGSM: -108dBm, DCS: -108dBm

TX output power GSM, EGSM: 32.5dBm(Level 5),

DCS , PCS: 29.5dBm(Level 0)

SIM card type 3V Small

Display MAIN : 1.45” TFT 128 ×128 pixel 65K Color

Status Indicator

Hard icons. Key Pad

0 ~ 9, #, *, Up/Down Left/Right Navigation Key

Send Key, PWR Key ,Soft Key(Left/Right)

ANT Internal

EAR Phone Jack Yes

PC Synchronization Not Support

Speech coding EFR/FR/HR

Data and Fax Yes

GPRS compatibility Not Support

Vibrator Yes

Loud Speaker Yes

Voice Recoding Not Support

Microphone Yes

2. SYSTEM SPECIFICATION

2.1 H/W Features

2. SYSTEM SPECIFICATION

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2. SYSTEM SPECIFICATION

Travel Adapter Yes

Speaker/Receiver 18x12Φ Speaker/ Receiver

MIDI 32 poly

Item Feature Comment

Camera Not Support

FM Radio Yes

2. SYSTEM SPECIFICATION

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2.2 Technical Specification

Item Description Specification

1 Frequency Band

EGSM

TX: 880 ~ 915MHz

RX: 925 ~ 960 MHz

DCS

TX: 1710 ~ 1785 MHz

RX: 1805 ~ 1880 MHz

2 Phase Error RMS < 5 degrees

Peak < 20 degrees

3 Frequency Error < 0.1 ppm

4 Power Level

Level Power Toler. Level Power Toler.

6 31dBm ±3dB 14 15dBm ±3dB

7 29dBm ±3dB 15 13dBm ±3dB

8 27dBm ±3dB 16 11dBm ±5dB

9 25dBm ±3dB 17 9dBm ±5dB

10 23dBm ±3dB 18 7dBm ±5dB

11 21dBm ±3dB 19 5dBm ±5dB

12 19dBm ±3dB

GSM850/EGSM

5 33dBm ±2dB 13 17dBm ±3dB

Level Power Toler. Level Power Toler.

1 28dBm ±3dB 9 12dBm ±4dB

2 26dBm ±3dB 10 10dBm ±4dB

3 24dBm ±3dB 11 8dBm ±4dB

4 22dBm ±3dB 12 6dBm ±4dB

5 20dBm ±3dB 13 4dBm ±4dB

6 18dBm ±3dB 14 2dBm ±5dB

7 16dBm ±3dB 15 0dBm ±5dB

DCS/PCS

0 30dBm ±2dB 8 14dBm ±3dB

2. SYSTEM SPECIFICATION

2.2 Technical Specication

2. SYSTEM SPECIFICATION

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5Output RF Spectrum

(due to modulation)

Offset from Carrier (kHz). Max. dBc

100 +0.5

200 -30

250 -33

400 -60

600~ <1,200 -60

1,200~ <1,800 -60

1,800~ <3,000 -63

3,000~ <6,000 -65

6,000 -71

GSM850/ EGSM

Offset from Carrier (kHz). Max. dBc

100 +0.5

200 -30

250 -33

400 -60

600~ <1,200 -60

1,200~ <1,800 -60

1,800~ <3,000 -65

3,000~ <6,000 -65

6,000 -73

DCS/PCS

Output RF Spectrum

(due to switching

transient)

GSM850/ EGSM

Offset from Carrier (kHz). Max. dBm

400 -19

600 -21

1,200 -21

1,800 -24

Item Description Specification

2. SYSTEM SPECIFICATION

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2. SYSTEM SPECIFICATION

Item Description Specification

Output RF Spectrum

(due to switching

transient)

Offset from Carrier (kHz). Max. dBm

400 -22

600 -24

1,200 -24

1,800 -27

7 Spurious Emissions Conduction, Emission Status

8 Bit Error Ratio

GSM850, EGSM

BER (Class II) < 2.439% @-102 dBm

DCS,PCS

BER (Class II) < 2.439% @-100 dBm

9 RX Level Report Accuracy ±3 dB

10 SLR 11±3 dB

11 Sending Response

300 -12

1,000 -6

2,000 -6

3,000 -6

Frequency (Hz)

100 -

200 -

4,000 -

3,400 -9

-12

12 RLR -5±3 dB

DCS/PCS

Max.(dB) Min.(dB)

2. SYSTEM SPECIFICATION

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2. SYSTEM SPECIFICATION

Item Description Specification

13 Receiving Response

300 -7

500 -5

1,000 -5

3,000 -5

100 -

200 -

4,000

3,400 -10

-12

14 STMR Over 17 dB

* Mean that Adopt a straight line in between 300 Hz and

1,000 Hz to be Max. level in the range.

15 Stability Margin > 6 dB

16 System frequency

(13 MHz) tolerance ≤ 2.5 ppm

17 32.768KHz tolerance ≤ 20 ppm

18 Ringer Volume

At least 65 dBspl under below conditions:

1. Ringer set as ringer.

2. Test distance set as 50 cm

19 Charge Current Fast Charge : Typ. 410 mA

Total Charging Time : < 3.5 hours

Frequency (Hz) Max.(dB) Min.(dB)

2. SYSTEM SPECIFICATION

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2. SYSTEM SPECIFICATION

Item Description Specification

2 -> 1

Bar Number Power

3 -> 2 -101±2

-93 ±2

20 Antenna Display

2 -> 1

1 -> 0

Battery Bar Number Voltage

3 -> 2 3.71 ±0.05 V

21 Battery Indicator

22 Low Voltage Warning

( Blinking Bar)

1 time per 1 minute (Receiver)

1 time per 3 minutes(Speaker)

23 Forced shut down

Voltage 3.3 3 ±0.05V

24 Battery Type

Lithium-Ion Battery

Standard Voltage = 3.7 V

Battery full charge voltage = 4.2 V

Capacity: 950mAh

25 Travel Charger

Switching-mode charger

Input: 100 ~ 240V, 50/60 Hz

Output: 4.8 V, 400 mA

> 3.72 ±0.05 V

3.65 ±0.05 V

3.51 ±0.05 V

5 -> 4

-106 ±2

1 -> 0

-104 ±2

-92 ±2

-97 ±2

4 -> 3

3. TECHNICAL BRIEF

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3. TECHNICAL BRIEF

3.1 Digital Main Processor

Figure. 3.1.1 MT6251 Hardware Block Diagram

3. TECHNICAL BRIEF

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3.TECHNICAL BRIEF

3.1.1 Platform features

General

r*OUFHSBUFE WPJDF-band , audio-band ,RF ,FM and base-band analog front ends

r'$$41NNYNN-ball , 0.5mm pitch package

MCU subsystem

r"SN&+-S 32-bit RISC processor

r)JHI-performance multi-layer AMBA bus

r0QFSBUJPO GSFRVFODZBU.I[

rTFUTPGHFOFSBM-Purpose timers.

r$JSDVJUTXJUDIEBUB DPQSPDFTTPS

r%JWJTJPODPQSPDFTTPS

Serial flash interface

r4VQQPSUT 41*BOE21*TFSJBMGMBTI

r4VQQPSUT PQFSBUJOH GSFRVFODZVQUP.)[

User interfaces

r-row x 5-column keypad controller with a hardware scanner

r4*.64*. DPOUSPMMFS XJUIIBSEXBSF55 QSPUPDPM DPOUSPM

r3FBM-time clock (RTC) operating with a separate power supply

r(FOFSBM-purpose I/Os (GPIOs)

rTFUPG1VMTF8JEUI.PEVMBUJPO 18.PVUQVU

r.BYJNVN FYUFSOBMJOUFSSVQU MJOFT

Connectivity

rTFUTPG6"35XJUIIBSEXBSF GMPXDPOUSPMBOETQFFEVQUP.CQT

r'4-4 64#EFWJDFDPOUSPMMFS

r%"*1$.BOE*4JOUFSGBDFGPSBVEJP BQQMJDBUJPO

3.1.2 Modem features

Radio interface and baseband front-end

r%'.USBOTNJUUFS IBT EJHJUBM 1.EBUB QBUIXJUIUIFCBTFCBOE GSPOU-end

rE#EZOBNJD SBOHFEFMUB-sigma ADC converts the downlink IF baseband

*BOE 2TJHOBMT UPUIFEJHJUBM CBTFCBOE

r-bit D/A converter for Automatic Power Control (APC)

r1SPHSBNNBCMF SBEJP 39GJMUFSXJUIBEBQUJWF CBOEXJEUI DPOUSPM

3.1.1 Platform features

3.1.2 Modem features

3. TECHNICAL BRIEF

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3.1.3 Multimedia features

LCD interface

r4FSJBM JOUFSGBDFGPS-$.

LCD controller

r4VQQPSUT -$.GPSNBUT 3(#3(#3(#3(#BOE3(#

r4VQQPSUT -$%NPEVMFXJUIUIFNBYJNVN SFTPMVUJPO VQUPYBUCQQ

Audio CODEC

r8BWFUBCMF TZOUIFTJT XJUIVQUPUPOFT

r1$.QMBZCBDL BOESFDPSE

r%JHJUBMBVEJP QMBZCBDL

Audio interface and audio front-end

r4VQQPSUT UIF*4JOUFSGBDF

r)JHI-resolution D/A converters for stereo audio playback

r4UFSFPUPNPOPDPOWFSTJPO

3.1.4 GSM RF features

Receiver

r0OFIJHICBOE BOEPOFMPXCBOE -/"TUPTVQQPSU USVFRVBE CBOE SFDFJWFS

r2VBESBUVSF RF mixers

rE#1(" HBJOXJUIE#HBJOTUFQ

Transmitter

r%JSFDU'SFRVFODZ.PEVMBUJPO %'.BSDIJUFDUVSF XJUI 1"QSF-amplifier

r-PX39CBOOPJTF

Digitally-controlled crystal oscillator (DCXO)

r5XP-pin 26MHz crystal oscillator

r0O-chip programmable capacitor array for coarse tune

3.1.5 FM features

r– 108 MHz worldwide FM bans with 50 kHz tuning step

r4VQQPSUT 3%43#%4SBEJP EBUB TZTUFN

r4VQQPSUT MPOHTIPSU BOUFOOBT

r4VQQPSUT L)[DMPDLBTSFGFSFODFDMPDL

r4PGUNVUFWPMVNFDPOUSPM

rE#4*/"%XJUIL)['.EFWJBUJPO

3.TECHNICAL BRIEF

3.1.3 Multimedia features

3. TECHNICAL BRIEF

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3.2 Power Management

A mobile platform requires power supplies for dierent functions. These power supplies are generated in the integrated

power management Unit (PMU). The PMU is designed to deliver the power for a typical standard phone.

Figure. 3.2.1 Block Figure of the PMU Modules MT6251

* DC/DC Step Down Converter with LDO Mode for 1.2V (VCORE)

The DC/DC converter generates a 1.2 V supply rail. This voltage rail is used to supply main parts of the system. Among

buck converters, VCORE also provide LDO mode for lower cost requirement.

Buck Mode LDO Mode

VCORE

LDO

VCORE

Buck

Controller

VCORE

LDO

VCORE

Buck

Controller

VBAT_VCORE

VCORE_FB

VCORE

VBAT_VCORE

VCORE

VCORE_FB

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3.TECHNICAL BRIEF

Linear voltage Regulators (low drop out) LDOs

The LDOs are used to generate the supply for the different supply domains not directly supplied out of the

DC/DC converter.

RF LDO (VRF)

The RF LDO is a linear regulator that could source 200mA (max) with 2.8V output voltage. It

supplies the RF circuitry of the handset. The LDO is optimized for high performance and

adequate quiescent current.

Digital IO LDO (VIO18, VIO28)

The digital IO LDO is a linear regulator that could source 200mA (max) with 2.8V output

voltage. It supplies the the power for baseband circuitry of the SoC.

Analog LDO (VA)

The analog LDO is a linear regulator that could source 150mA (max) with 2.8V output voltage.

It supplies the analog sections of the SoC. The LDO is optimized for low frequency ripple

rejection in order to reject the ripple coming from the burst at 217Hz of RF power amplifier.

TCXO LDO (VTCXO)

The TCXO LDO is a linear regulator that could source 40mA (max) with 2.8V output voltage.

It supplies the temperature compensated crystal oscillator, which needs ultra low noise supply

with very good ripple rejection.

Single-Step RTC LDO (VRTC)

The single-step RTC LDO is a linear regulator that can charge up a capacitor-type backup coin

cell to 2.8V, which also supplies the RTC module even at the absence of the main battery. The

single-step LDO features the reverse current protection and is optimized for ultra low quiescent

current while sustaining the RTC function as long as possible.

Memory LDO (VSF)

The memory LDO is a linear regulator that could source 50mA (max) with 1.8V or 3V

output voltage selection based on the supply Serial flash memory

SIM LDO (VSIM1,2)

The SIM LDO is a linear regulator that could source 100mA (max) with 1.8V or 3.0V output

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3.TECHNICAL BRIEF

Table. 3.2.2 Power supply Domains

SIM LDO (VSIM1,2)

The SIM LDO is a linear regulator that could source 100mA (max) with 1.8V or 3.0V output

USB LDO (VUSB)

The USB LDO is a linear regulator that could source 50mA (max) with 3.3V output dedicated

for USB circuitry.

FM LDO (VFM)

The VFM LDO is a linear regulator that could source 40mA (max) with 2.8V output for internal FM chip.

VIBR LDO (VIBR)

The VIBR LDO is a linear regulator that could source 200mA (max) with 1.3V, 1.5V, 1.8V, 2.5V, 2.8V,

3.0V or 3.3V output for Vibrator.

Type LDO name Vout(V) Imax(mA) Description

ALDO VRF 2.8 200 RF chip

ALDO VA 2.8 150 Analog baseband

ALDO VTCXO 2.8 40 13/26 MHz reference clock

ALDO VFM 2.8 40 FM Chip power

DLDO VIO28 2.8 200 Digital IO

DLDO VSIM 1.8/3.0 100 SIM card

DLDO VSIM2 1.3/1.5/1.8/2.5

2.8/3.0/3.3 50 SIM card

DLDO VUSB 3.3 50 USB

DLDO VIO18 1.8 200 Digtal IO

DLDO VIBR 1.3/1.5/1.8/2.5

2.8/3.0/3.3 200 Vibrator

DLDO VSF 1.8/3 50 Serial ash power

RTCLDO VRTC 2.8 2 Real-time clock

Table.3.2.2 Power supply Comains

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3.TECHNICAL BRIEF

3.2.1 Power on and startup

There are three methods to power-on the handset system (When VBAT >= 3.2V)

Push PWRKEY (Pull the PWRKEY pin to the low level)

Pulling PWRKEY low is the typical way to turn on the handset. The VCORE buck converter will be turned on,

the VIO28/VA LDOs and VUSB LDO, VRF/VTCXO LDOs will be turned on finally. The supplies for the baseband

will be ready, and the system reset will end at the moment when the LDOs is fully turned on to ensure the

correct timing and function. After that, the baseband will send the PWRBB signal back to the PMU for

acknowledgement. To successfully power-on the handset, PWRKEY should be kept low until the PMU receives

the PWRBB from the baseband.

RTC module generates PWRBB to wake up the system.

If the RTC module is scheduled to wake up the handset at some time, the PWRBB signal will directly be sent to

the PMU. In this case, PWRBB will become high at a specific moment and allow PMU to be powered-on just

like the sequence described above. The function is called “RTC alarm”

Valid charger plug-in (CHRIN voltage is within the valid range.)

Plugging in the charger will also turn on the handset if the charger is valid (no OVP taken place). However, if

the battery voltage is too low to power-on the handset (UVLO state), the system will not be turned on by any

powered-on automatically as long as the battery voltage is high enough.

Under-Voltage Lockout(UVLO)

The UVLO state in the PMU prevents start-ups if the initial voltage of the main battery is below the 3.2V

threshold. When the battery voltage is gradually lowering, it will enter the UVLO state, and the PMU will be

turned off by itself, except for VRTC LDO, to prevent further discharging.

3.2.1 Power on and startup

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