LG A258 Service Manual

Internal Use Only

Service Manual

LG-A258

Date: June, 2011 / Issue 1.0

- 2 -

Only for training and service purposes

Table Of Contents

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

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

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

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

2. PERFORMANCE .................................................................... 7

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

2.2 Technical Speciﬁcation ........................................................................9

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

3.1 LG-A258 Functional Block Diagram ............................................ 14

3.2 Digital Main Processor (PMB8815, U200) ................................. 15

3.3 Power Management ......................................................................... 20

3.4 FEM with integrated Power Ampliﬁer Module

(SKY77550, U301) ...............................................................................33

3.5 Crystal(26 MHz, X100) ...................................................................... 36

3.6 RF Subsystem of PMB8815 (U101) .............................................. 37

3.7 MEMORY ................................................................................................ 40

3.8 Bluetooth module .............................................................................. 45

3.9 SIM Card Interface .............................................................................. 47

3.10 LCD Interface .....................................................................................48

3.11 Vibrator Interface .............................................................................49

3.12 MINI ABB Interface .......................................................................... 50

3.13 Keypad Interface .............................................................................. 53

3.14 Audio Front-End ............................................................................... 55

3.15 Camera Interface .............................................................................. 61

3.16 KEY BACLKLIGHT LED Interface ................................................. 63

4. TROUBLE SHOOTING ........................................................64

4.1 Trouble shooting test setup ........................................................... 64

4.2 RF Component .................................................................................... 65

4.3 RX Trouble ............................................................................................. 66

4.4 TX Trouble .............................................................................................. 72

4.5 Power On Trouble ............................................................................... 78

4.6 Charging Trouble ................................................................................ 81

4.7 Vibrator Trouble .................................................................................. 84

4.8 LCD Trouble .......................................................................................... 87

4.9 Camera Trouble ................................................................................... 91

4.10 Speaker Trouble ................................................................................ 94

4.11 Earphone Trouble ............................................................................97

4.12 Micro SD Trouble

4.13 Bluetooth Trouble ..........................................................................104

4.14 FM Radio Trouble ...........................................................................106

5. DOWNLOAD .....................................................................109

6. BLOCK DIAGRAM .............................................................122

7. CIRCUIT DIAGRAM ..........................................................123

8. BGA PIN MAP ..................................................................128

9. PCB LAYOUT .....................................................................130

10. STAND ALONE TEST ......................................................132

10.1 Introduction .....................................................................................132

10.2 Setting Method ..............................................................................132

10.3 Tx Test .................................................................................................134

10.4 Rx Test .................................................................................................135

11.AUTO CALIBRATION .......................................................136

11.1 Overview ...........................................................................................136

11.2 Directory structure of Tachyon .................................................136

11.3 Description of Folder & File. .......................................................137

11.4 Procedure ..........................................................................................138

11.5 Tachyon Main UI .............................................................................139

11.6 AGC ......................................................................................................140

11.7 APC ......................................................................................................140

11.8 ADC ......................................................................................................140

11.9 Target Power ....................................................................................140

12. EXPLODED VIEW & REPLACEMENT PART LIST ..........141

12.1 EXPLODED VIEW .............................................................................141

12.2 Replacement Parts ........................................................................142

12.3 Accessory ..........................................................................................157

............................................................................102

1. INTRODUCTION

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

- 3 -

Only for training and service purposes

- 4 -

Only for training and service purposes

1. INTRODUCTION

E. Notice of Radiated Emissions

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

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

the following to the end user.

F. Pictures

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

G. Interference and Attenuation

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

unsuppressed engines or electric motors may cause problems.

H. Electrostatic Sensitive Devices

ATTENTION Boards, which contain Electrostatic Sensitive Device (ESD), are indicated by the sign. Following information is ESD handling:

• Service personnel should ground themselves by using a wrist strap when exchange system boards.

• When repairs are made to a system board, they should spread the floor with anti-static mat which is also

grounded.

• Use a suitable, grounded soldering iron.

• Keep sensitive parts in these protective packages until these are used.

• When returning system boards or parts like EEPROM to the factory, use the protective package as described.

1.3 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

- 5 -

Only for training and service purposes

1. INTRODUCTION

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

- 6 -

Only for training and service purposes

2. PERFORMANCE

2.1 H/W Features

Item Feature Comment

Standard Battery Lithium-ion r, 3.7V, 900mAh

Stand by TIME

Up to 290 hrs ( Paging Period 5, RSSI -85dBm )

Talk time Up to 361min : GSM Tx Level 7

Charging time Approx. 3 hours

TX output power

GSM, EGSM: 33dBm(Level 5), DCS , PCS: 30dBm(Level 0)

SIM card type 3V Small

Display

MAIN : 2.2” TFT 176 Ý 220 pixel 262K Color Sub : 0.968 mono 96 x 64

Status Indicator

Button (Outside) Send Key, End Key, Navi Key(4EA), OK Key, Menu Key, Contacts Key Button (Inside) Numeric Key 12EA

ANT Internal

EAR Phone Jack 5PIN I/O

PC Synchronization Yes

Speech coding

EFR/FR/HR/AMR

Data and Fax Yes

GPRS compatibility Class 12

Vibrator Yes

Loud Speaker Yes

Voice Recoding Yes

Microphone Yes

RX Sensitivity

GSM, EGSM: -109dBm, DCS: -109dBm

2. PERFORMANCE

- 7 -

Only for training and service purposes

- 8 -

Only for training and service purposes

2. PERFORMANCE

Travel Adapter Yes

Speaker/Receiver 18x12Ȱ Speaker/ Receiver

MIDI SW MIDI (Mono SPK)

Item Feature Comment

Camera 1.3M

Bluetooth / FM Radio Bluetooth version 2.1 / 76~108MHz supported

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

GSM850

TX: 824 ~ 849 MHz RX: 869 ~ 894 MHz

PCS

TX: 1850 ~ 1910 MHz RX: 1930 ~ 1990 MHz

2. PERFORMANCE

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Only for training and service purposes

- 10 -

Only for training and service purposes

2. PERFORMANCE

Output 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

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% @-102 dBm

9 RX Level Report Accuracy ·3 dB

10 SLR 14·3 dB

11 Sending Response

300 -12

1,000 -6

2,000 -6

3,000 -6

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

100 -

200 -

4,000 -

3,400 -9

-12

12 RLR 4·3 dB

DCS/PCS

2. PERFORMANCE

- 11 -

Only for training and service purposes

- 12 -

Only for training and service purposes

2. PERFORMANCE

Item Description Specification

13 Receiving Response

300 -7

500 -5

1,000 -5

3,000 -5

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

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

-20

-10

dB to ARL (dB) Level Ratio (dB)

-35

-30

30.7

33.3

33.7

31.7

17.5

22.5

25.5

16 Distortion

17 Side Tone Distortion Three stage distortion < 10%

System frequency (26 MHz) tolerance

˺ 2.5 ppm

19 32.768KHz tolerance ˺ 30 ppm

20 Ringer Volume

At least 58 dB SPL under below conditions:

1. Ringer set as ringer.

2. Test distance set as 100 cm

Item Description Specification

21 Charge Current

Fast Charge : Typ. 400 mA

Slow Charge : Typ. 400mA

Total Charging Time : < 3 hours

2 -> 1

0 -> OFF

Bar Number Power

4 -> 2

-104 · 2

-106 Under

-98 · 2

-101 · 2

22 Antenna Display

23 Battery Indicator

Low Voltage Warning

( Blinking Bar)

Forced shut down

Voltage

3.35 · 0.05V

27 Battery Type

Lithium-Ion Battery Standard Voltage = 3.7 V Battery full charge voltage = 4.2 V Capacity: 900mAh

28 Travel Charger

Switching-mode charger Input: 100 ~ 240V, 50/60 Hz Output: 5.1V, 400 mA

Sustain RTC

without battery

Over 30 sec

7 -> 5

5 -> 4

-92 Over

-93 · 2

1 -> 0 -106 · 2

It alarms 3 times (standby)10% : 1

warning 5% : 2

warning 0% : 3rdwarning It alarms every 1min under 10%(call)

13 level(Full)

2 / 2

100~93%

92~85%

84~77%

76~70%

69~62%

61~54%

46~39%

30~24%

38~31%

23~16%

15~11% 10~8%

7 53~47%

7~1%

2. PERFORMANCE

- 13 -

Only for training and service purposes

- 14 -

Only for training and service purposes

3. TECHNICAL BRIEF

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3.1 LG-A258 Functional Block Diagram

The functional component arrangement is mentioned below diagram.

Figure. 3.1.1 LG-A258 Functional Block Diagram

FM - radio

Digi tal -

Mic rophone

ARM11 76

RAM ROMcac he

Ext ernal

Mem ory- IF

USI F

Mea surem ent

IF (A/D)

SD/ MM C SIM

GSM

TEA KLite

Co ntro l

GSM

Ci pher

GPT U

I² S / DA I

IR - M emor y

Loud spe aker

Mic Supply gener ation

HSR

HSL

EPP

EPN

LSP

LSN

MI CP1

MI CN1

MI CP2

MI CN2

Mic

MU X

VM IC

VUM IC

16 O hm 100 m W

8 Ohm

700 m W

2x 16 Ohm 2x 30 mW

Ster eo Hea dset

Earpie ce

Cha rge Pu mp (n egativ e vo ltage for bipola r audio out )

VMM C

VAN ALPM U

VUS B

LA UX

Ch arg e

DC/ D C

Bu ck

Vib rato r

64 - b it b us 32 - b it b us

GMS K

DA C

PLL

FEM

32 kH z

DSPAD C

c s iM

Lo wPow er DC XO

RF PM U

USB 2.0

CI F

DC C

Key pad

4k7

0. 15 5 %

1.8V ~2.5V

VCHARGE 4. 5 V … 20V

ESNE

PES

C S B

GHC

BC 847 S

1 2

for example

ZXT P 25020

min.

10 µF

(0 V ) 3.05 V … 5.1 V (6 V)

002

>ef

T 1

7.5µA

135 mV … 600mV

4k3

127k

470

1.0V…

1,8V

Vco re

LR TC

LSI M

Bac k -

lig ht

LDO bloc king c aps, 100 nF

DC/ DC

Batt ery Charge r

3.2 Digital Main Processor (PMB8815, U101)

3. TECHNICAL BRIEF

Figure. 3.2.1 X-Gold 215 Hardware Block Diagram

Only for training and service purposes

- 15 -

- 16 -

Only for training and service purposes

3. TECHNICAL BRIEF

3.2.1 General

Technology: – SoC, Monolithic, 65 nm CMOS

• Package: – eWLB, 8x9x0.8 mm – 0.5 mm pitch – 240 balls / 6-layer PCB

3.2.2 RF Transceiver

• Dual-band direct conversion receiver

• Tri/Quad-band possible with external circuitry

• Fully integrated digital controlled X0

• Additional buffer for 2 external system clocks

• Fully digital RF-Synthesizer incl. ȭȟ-Transmitter

3.2.3 Baseband

• DSP: – 178 MHz TeakLite™

• MCU: – ARM ® 1176 @ 208 MHz

• MCU RAM: – 3.00Mbit

• Memory I/F: – 1Gbit NOR flash/One NAND flash/SDR SDRAM – 4Gbit NAND flash/DDR SDRAM

• Modem:

– GPRS class 12, (RX/TX CS1-CS4) – EGPRS class 12, (RX MCS1-MCS9, TX MCS1-MCS4)

• Cipher Units:

– A51/2/3 – GEA-1/2/3

• Security:

– OMTP TR0 – Secure Boot – RSA(ROM)/SHA-1(HW accel.) – OCDS disabling – Certificate Management

• Speech Codec: – FR / HR / EFR / NB-AMR

• Audio Codec (running on ARM1176): – SP-MIDI – SB-ADPCM – MP3 – WB-AMR – AAC/AAC+/eAAC+

• Others: – DARP (SAIC) – TTY

• Customization: – E-Fuses

3.2.4 External Memory

• External Bus Unit – 16-bit address bus – 16-bit address/data muxed bus – 1.8V support

• Flash / RAM – NOR Type – NAND Type(1bit ECC supported) – Parallel Flash/Cellular RAM(Page & Burst Mode)

- 16-bit AD-multiplexed(concurrent usage of DDR interface and AD-multiplexed interface is not supported)

- 16-bit AAD-multiplexed – iNAND Type e.g. oneNAND – SDRAM

- DDR SDRAM : up to 4 Gbit

- SDR SDRAM : up to 1 Gbit

• Memory card – SD/MMC card interface with 1 or 4 data lines

3.2.5 Connectivity

• Up to 3xUSIF (configurable either as SPI or UART), I2C, I2S; Interfaces @ 1.8V

• Direct (U)SIM 1.8/3V

• USB2.0 up to 480 Mbit/s (High Speed) w/ external USB Phy over ULPI interface

• Stereo Headset (Amplifier integrated)

• 3 external analog measurement PIN’s

• Bluetooth, A-GPS, WLAN support (I2C, I2S, SPI)

3. TECHNICAL BRIEF

- 17 -

Only for training and service purposes

- 18 -

Only for training and service purposes

3. TECHNICAL BRIEF

3.2.6 Mixed Signal

• Improved audio performance

• Loudspeaker Audio Class D Amplifier, 700 mW@8 ȳ mono for hands-free and ringing

• Stereo Headset 2x30 mW@16 ȳ w/o coupling C

• Mono Earpiece 100 mW@16 ȳ

• Digital microphone supported

• Differential microphone input

3.2.7 FM Radio

• Integrated FM radio – FM Stereo RDS Receiver – Sensitivity 2 ɆV EMF – Support for US & EU bands – Stereo recording

3.2.8 Power Management

• Direct-to-Battery Connection – LDOs (incl. capless) – DC/DC step-down converter – DC/DC step-up for white LED supply

• Battery Type – Li-Ion

• Charging control – Battery temperature – Watchdog protection – Start-up on flat battery

• External Charger – Switch mode

• USB battery charging – USB charging spec 1.0 compliant

• Backlight – Up to 4 serial white LEDs (integrated LDO)

3. TECHNICAL BRIEF

3.2.9 Display

• Type

– 128x160, 65k color (serial)

– QVGA, 262k color (parallel)

• Interface

– Parallel 8/9bit MIPI-DBI Type B

– Serial MIPI-DBI Type C

– Interf. voltage at 1.8V or 2.8V

• gRacr - Display Controller (Hardware)

– 30 fps Display update without DMA (up to 60 fps) (full or partial) – Video post processing Scaling, Rotation (90¶ steps), Mirroring

– Overlay with alpha blending

– Color conversion YUV -> RGB

– 2D vector graphics (Lines, filled rectangles, Bit block transfer (e.g. sprites, scrolling, antialiased bitmap fonts)

3.2.10 Camera

• 2 Mpx YUV parallel interface

• HW JPEG encoder (39 Mpx/sec)

• 39 MHz Pixel Rate

• 15 fps@ 2 Mpx full resolution

3.2.11 Video Capabilities

• Video Decoding MPEG-4/H.263

– QCIF@30 fps

– QVGA@15fps

• Video Encoding MPEG-4/H.263

– QCIF@15 fps

3.2.12 Audio Capabilities

• Polyphonic ring tones

– 64 voices MIDI, SP-MIDI

– FM synthesizer

• AMR-WB

• True ring tones (MP3)

• MP3, eAAC+

• G.722 SB-ADPCM encoding/decoding

- 19 -

Only for training and service purposes

- 20 -

Only for training and service purposes

3. TECHNICAL BRIEF

3.3 Power Management

A mobile platform requires power supplies for different 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 X-Gold tm 215

 DC/DC Step Down Converter for 1.8V (SD1)

The DC/DC converter generates a 1.8V supply rail. This voltage rail is used to supply main parts of the system,

like the digital core of the chip (via LDO LCORE), some parts of the mixed signal macro, parts of the RF macro

and the external memory if a 1.8V memory is used. The efficiency of the DC/DC converter is optimized for an

average load current of 100mA. That is the load current estimated for the GSM talk mode.

3. TECHNICAL BRIEF

 Linear voltage Regulators (low dropout) LDOs

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

DC/DC converter.

 LCORE

The LCORE LDO provides the VCORE supply used for most of the digital parts of the chip

 LPMU

The LPMU provides VPMU sued for the PMU supply, e.g. for the startup state machine and analog parts like

ADC, sense amplifier etc.

 LUSB

The LUSB LDO generates the supply for the USB transceiver (output driver and input). If no USB interface is

required, LUSB can be used as general purpose LDO.

 LAUX

The LAUX generates VAUX. It is a general purpose LDO and can be used for different functions depending on

the phone application, e.g. for the display or Camera.

 LMMC

The LMMC generates VMMC. It is a general purpose LDO and can be used e,g. for memory cards

 LSIM

The LSIM LDO generates the VSIM supply for the SIM card and interface. It is designed to supply Standard SIM

cards according ETSI TS 102 221.

 Other LDOs

• The RF module has implemented several LDO’s for different RF power domains.

• The mixed signal module has some LDO’s for the audio driver and microphone supply

• The FM receiver has an internal LDO for sensitive RF circuits.

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Only for training and service purposes

- 22 -

Only for training and service purposes

3. TECHNICAL BRIEF

Table. 3.3.1 Power supply Domains (without RF)

3. TECHNICAL BRIEF

3.3.1 Power on and startup

 Analog startup Circuit

Because the POR circuit and the LPBG are directly connected to the battery, it is not possible to switch them

off. If the battery voltage exceed the power on reset threshold (2.5V), the power on reset is released, the LPMU

regulator and the LRTC voltage regulator are switched on. The LPMU regulator starts in its ultra-low power

mode

The LPMU regulator generates a control signal (lpmu_OK) that enables the 50KHZ PMU oscillator. The output

clock of the oscillator is checked with a fully coded counter. A counter overflow releases the reset

(vpmu_rst_n) signal for the small PMU state-machine.

 Small first digital State-Machine

The small PMU state-machine is always connected to VPMU After starting from reset the small startup state

machine enters the SYSTEM OFF state and only continuous the startup procedure if a switch on event like first

connect, on-key, wake up or charge detect occurs.

 PMU-main State-Machine

The main PMU state-machine is always connected to VPMU also. The power up sequence driven by the PMU

state-machine can be seen in Figure18. After enabling the reference (HPGB) and waiting for the settling time,

the battery voltage is measured and compared with the power on threshold. If the battery voltage is high

enough, the SD1 DC/DC converter and the LCORE LDO are started. A timer ensures that the supply voltage

will be stable before the DCXO is enabled. The DCXO settling time is ensured using a fixed timer. After an

overflow of this timer, the reset is released for the rest of the system. The PMU state machine remains in this

System-ON state until the system is switched into the OFF state. For example the system sleep mode is

completely configured by software( for example switching off the LDO’s, switching of the DCXO etc.) and

controlled by the VCXO_enable signal. The reason for the startup is stored in the ResetSourceRead register.

 Battery Measurement

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3. TECHNICAL BRIEF

The ADC and the oscillator for the ADC needs the VDD_ADC supply voltage from the LADC LDO. LADC uses either the charger voltage VDD_CHARGE or VDDRTC as input voltage. The input voltage is selected automatically by a bulk switch circuit. LADC, the ADC and the oscillator are enabled on request for every battery measurement if the charger unit is not running. This is handled by an ADC control block in one of the statemachines. If the charger unit is running the ADC is controlled by the charger state-machine

Figure.3.3.2 First Part of the State Machine, Running in Different Power Domains than the Second Part

3. TECHNICAL BRIEF

Figure 3.3.3 Second (Main) Part of the Startup State Machine in the VPMU Domain

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3. TECHNICAL BRIEF

3.3.2 Switching on due to first connect

If the battery voltage is connected the first time, that means the system enters the first time the SYSOFF state,

this is stored in a first connect flag. If the first connect flag is set, the system will start immediately and not wait

for any other system on event in the SYSOFF state.

3.3.3 Switching on due to on-Key event

The on key is connected to the ONKEY pad. The ESD protection and the input structure of this pad are

connected to VRTC. If the ONKEY pad is forced to VRTC by an external key or similar circuit, the system starts.

The ONKEY is sampled with the PMU clock. It has to be sampled four times high before a valid on event is

generated. The status of the ON key can be read in the PMU registers, so it can be used as a functional key

during phone operation also

3.3.4 Switching on due to RTC alarm

The real time clock can generate a wakeup signal called RTC alarm. This signal is sampled from the state-

machine and after successfully detecting a high, the system is switched on.

3.3.5 Switching on due to charging

When a battery with a voltage below the SSONLEV level is inserted, the state machine will not start the system.

As long as the battery voltage stays lover than SYSONLEV the system will stay off. The only possibility to start

up the system is due to an external charger.

If an external charger is connected and detected and the battery is charged above the SYSONPRE voltage level

the system will start up.

The PMU main state machine waits in the Check battery state until the battery voltage condition is fulfilled.

The charger state machine provides the necessary pre-charge indication signal. This pre-charge signal is

denounced in a small counter to have a stable signal. This is important, especially in half/full-wave charging

where the charger detection is switching between charger detected/not detected according the AC supply

frequency. reasons

For details on pre-charging see the charger chapter. The charger is controlled by an independent state

machine. The pre-charge signal is used to trigger the pre-charge signal is used to trigger the pre-charge

functionality. The charger state machine fully control the pre-charge, the PMU-state machine now changes to

state HPBG on state and the system starts. This state change is indicated to the charger state-machine to

enable the charger watchdog for safety

3. TECHNICAL BRIEF

3.3.6 Power Supply Start-up sequence

In order to avoid an excessive drop on the battery voltage caused by in-rush current during system power-on,

possibly leading to system instability and “hick-ups” a staggered turn-on approach for the regulators is

implemented. The regulators are turned on in a well defined sequence, thus spreading the in-rush current

transients over time.

The IO’s of X-GOLD TM 215 are isolated in OFF mode (core supply is off). The isolation signal is controlled by

the PMU state machine. This ensures that the PADs are in a well defined state during core supply settling. This

allows to power up the LCORE core regulator and wait for the core to reach reset state before powering up the

I/O supply regulators.

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3. TECHNICAL BRIEF

Figure 3.3.4 Start Up Sequence (triggered by First Connect Event)

3. TECHNICAL BRIEF

3.3.7 External Reset Handling

The chip reset can be controlled by an external RESET_N ball. If this ball is pulled low, the chip will be reset.

All PMU registers are reset during the external reset including LSIM control bits. The PMU statemachines are

also not reset from the external reset. An SW or watchdog reset will not reset the PMU registers. A SW and

Watchdog reset is seen on the reset_n pad to allow the reset of external devices. Basically there are three reset

sources, first the reset signal controlled by the PMU (reset_pmu_n_o), second the reset signal controlled by the

SCU (resetout_o) and third the external reset (RESET_N). The SCU reset is triggered by SW (for example due to a

SW reset or watchdog reset). The PMU reset is controlled by the PMU state machine. The output of the reset handling block is the reset_postscu_n_o signal. This signal controls for example the ɆC subsystem and releases

reset for the controller. During normal start up, the PMU releases the reset_pmu_n_o signal after entering the

SYSTEM ON state. At this time the resetout_o signal is high, the RESET_N pad is not pulled low and therefore the reset_postscu_n_o signal follows the reset_pmu_n_o signal. That means the ɆC reset will be released and the ɆC starts operation. If the SW triggers an external reset via the SCU, signal resetout_o will be forced to low

for a certain time and RESET_N will be forced to low by the open drain driver. At the same time the feedback to

the SCU will be masked to not reset the baseband. The RESET_N pad is in the VDDRTC domain but the internal

pull up is connected to the VDD_VDIG1 (1.8V) domain. That allows the pad to be used as reset for external

devices running in the VDD1V8 domain. The RESET_N pad can also be used to monitor the chip internal reset

condition during startup.

The open drain driver is a weak driver, that means it can be forced to high during debug from external pushing

some current into the pad. In testmode signal reset_pmu_n_o is high, that means the chip reset is fully

controlled from external

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3. TECHNICAL BRIEF

3.3.8 Sysclock Switching

The PMU controls the rf_sysclk_en signal of the DCXO in the RF macro. During startup the PMU enables the

DCXO. After the system is running the DCXO is controlled by the SCU of the baseband by using the

vcxo_enable signal. This is handled by a dedicated logic in the PMU, see Figure 3.3.6. As long as

rf_sysclk_en_pmu, the output of the PMU state-machine is high, vcxo_enable controls the rf_sysclk_en signal

to the RF. If rf_sysclk_en_pmu is low, the DXCO is switched off, independent from vcxo_enable.

Figure 3.3.5 PMU, CGU and External Reset

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LG A258 Service Manual

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