LG A100 Service Manual

Internal Use Only

Service Manual

LG-A100

Date: March, 2011 / Issue 1.0

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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. PERFORMANCE ...................................................................... 7

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

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

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

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

3.2 Power Management ............................................................................ 18

3.3 FEM with integrated Power Ampliﬁer Module

(SKY77550, U301) .................................................................................. 30

3.4 Crystal(26 MHz, X102) .........................................................................32

3.5 RF Subsystem of PMB8810 (U101) .................................................32

3.6 MEMORY(FM25Q32, U102) ............................................................... 36

3.7 SIM Card Interface ................................................................................. 38

3.8 Display Interface .................................................................................... 39

3.9 Battery Charger Interface ................................................................... 41

3.10 Keypad Interface ................................................................................. 42

3.11 Audio Front-End .................................................................................. 44

3.12 KEY BACLKLIGHT LED Interface .................................................... 50

3.13 Vibrator Interface ................................................................................ 51

3.14 Torch LED Interface ............................................................................ 52

4. TROUBLE SHOOTING .......................................................... 53

4.1 RF Component ....................................................................................... 53

4.11 SIM Card Interface Trouble .............................................................. 80

4.12 KEY backlight Trouble ....................................................................... 82

5. DOWNLOAD ......................................................................... 85

6. BLOCK DIAGRAM .................................................................98

7. CIRCUIT DIAGRAM .............................................................. 99

8. BGA PIN MAP

9. PCB LAYOUT .......................................................................104

10. ENGINEERING MODE ......................................................106

11. AUTO CALIBRATION ........................................................107

11.1 Overview ..............................................................................................107

11.2 Directory structure of Tachyon ....................................................107

11.3 Description of Folder & File...........................................................108

11.4 Procedure .............................................................................................109

11.5 Tachyon Main UI ................................................................................110

11.6 AGC .........................................................................................................111

11.7 APC .........................................................................................................111

11.8 ADC .........................................................................................................111

11.9 Target Power .......................................................................................111

12. EXPLODED VIEW & REPLACEMENT PART LIST .............112

12.1 EXPLODED VIEW ................................................................................112

12.2 Replacement Parts ...........................................................................113

12.3 Accessory .............................................................................................123

....................................................................103

4.2 RX Trouble ................................................................................................ 54

4.3 TX Trouble ................................................................................................. 58

4.4 Power On Trouble .................................................................................. 62

4.5 Charging Trouble ................................................................................... 65

4.6 Vibrator Trouble ..................................................................................... 67

4.7 LCD Trouble ............................................................................................. 69

4.8 Speaker Trouble ..................................................................................... 72

4.9 Earphone Trouble .................................................................................. 75

4.10 Microphone Trouble .......................................................................... 78

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

LGE Internal Use Only

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LGE Internal Use Only

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

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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

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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 9 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 : 1.5” TFT 128 Ý 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. PERFORMANCE

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2. PERFORMANCE

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Travel Adapter Yes

Speaker/Receiver 18x12Ȱ Speaker/ Receiver

MIDI 32 poly

Item Feature Comment

Camera

Not Support

FM Radio Yes

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. PERFORMANCE

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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% @-100 dBm

9 RX Level Report Accuracy ·3 dB

10 SLR 13·4 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 2·3 dB

DCS/PCS

Max.(dB) Min.(dB)

2. PERFORMANCE

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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 17 dB 㢨ㇵ

* 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

System frequency (13 MHz) tolerance

˺ 2.5 ppm

17 32.768KHz tolerance ˺ 30 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. 400 mA

Total Charging Time : < 3.5 hours

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

Over 17 dB

Item Description Specification

2 -> 1

Bar Number Power

4 -> 2

-101· 2

-93 · 2

20 Antenna Display

2 -> 1

1 -> 0

Battery Bar Number Voltage

3 -> 2

3.75 · 0.05 V

21 Battery Indicator

Low Voltage Warning

( Blinking Bar)

1 time per 1 minute (Receiver)

1 time per 3 minute (Speaker)

Forced shut down

Voltage

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

> 3.75· 0.05 V

3.67 · 0.05 V

3.6 · 0.05 V

5 -> 4

-106 · 2

1 -> 0

-104 · 2

-92 · 2

2. PERFORMANCE

LGE Internal Use Only

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3. TECHNICAL BRIEF

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3.1 Digital Main Processor

Figure. 3.1.1 X-Gold tm 110 Hardware Block Diagram

3. TECHNICAL BRIEF

3.1.1 General

Technology: – SoC, Monolithic, 65 nm CMOS

• Package: – WFWLB, 8x8x0.8 mm – 0.5 mm pitch – 217 balls

3.1.2 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

3.1.3 Baseband

• High performance fixed-point TEAKlite DSP

• C166S-V2 high performance microcontroller with a 16KB Instruction Cache and a Data cache Buffer.

• FM Stereo Radio Receiver with RDS

• There are several Interfaces: – I2S interface for DAI connections (for Tape Approval) and external Audio component connection. – High Speed SSC Interface for connection of companion chips (like Serial SD Cards) – High Speed SSC Interface dedicated to Display control – USIM Interface with support of Protocol T=1 and Dual USIM support. – Keypad Interface (6x4 or 5x5 keys) – External Memory Controller (EBU) for external RAM/NOR FLASH/Busrt Flash/NAND Flash/Serial Flash

(SPI/SQI) and Parallel Display connection – Asynchronous serial interface. – Asynchronous serial interface for WLAN/BT/GPS control (incl. IrDA support capability) . – JTAG Interface, OCDS, Multi-Core Debug and Real Time Trace facilities. – Black & white and 128x160 - 16bit color displays are supported – PWM source to drive vibrator – Keypad and display backlight supported. – HASH Unit support for hashing.

3. TECHNICAL BRIEF

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Crystal Oscillator

• Fully digital controlled crystal oscillator core with a highly linear tuning characteristic

Mixed Signal and Power Management Unit

• Embedded stepdown converter (1.8V)

• DC/DC boost for voltages up to 15 V for driving White or Blue LEDs

• 8-ȳ loud speaker driver (700 mW)

• 16-ȳ earpiece driver

• 32-ȳ headset driver

• Measurement interfaces (PA temperature, battery voltage, battery temperature, and ambient temperature)

• Accessory Detection

• PCB ID detection as part of measurement interface.

• Differential microphone input

• System start up circuitry

• Charger circuitry for NiCd, NiMh and LiIon cells with integrated Control Current/Voltage Charging.

• Integrated regulators for direct connection to battery.

C166S-V2 Buses

The C166S-V2 is connected to four buses:

1. IMB (Internal Program) bus (64b - 0 cycle instruction bus))

2. DPMI (Data-Program) Bus (16b - 0 cycle data bus)

3. X-Bus (16b - 3 cycle peripheral bus)

4. PD-Bus (16b 0 cycle peripheral bus)

Bus Interconnections

The interconnection between the X-Bus and the TEAKlite Bus uses:

• Multicore Synchronization

• Shared Memory.

3. TECHNICAL BRIEF

3.1.4 FM Radio

• Not supported

3.1.5 Display

• Type

– 128*128, QQVGA, 65k color (parallel)

• Interface

– Parallel 8/9bit MIPI-DBI Type B

– 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)

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3.2 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 110

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

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

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

macro and the external memory if a 1.8V memory is used.

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.

 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.

 LSIM

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

cards.

 Other LDOs

The RF module has implemented several LDO’s for different RF Power domain.

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

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LGE Internal Use Only

Table. 3-2-1 Power supply Domains (without RF)

3. TECHNICAL BRIEF

3.2.1 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

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LGE Internal Use Only

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

3. TECHNICAL BRIEF

Figure 3.2.2 Second (Main) Part of the Startup State Machine in the VPMU Domain

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3.2.2 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.

3.2.3 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

3.2.4 Switching on due to RTC alarm

The real time clock can generate a wakeup signal called RTC alarm. This signal is sampled from the statemachine and after successfully detecting a high, the system is switched on.

3.2.5 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

3. TECHNICAL BRIEF

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

3.2.6 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 213 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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Figure 3.2.3 Start Up Sequence (triggered by First Connect Event)

3. TECHNICAL BRIEF

3.2.7 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 21. 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 3.2.4 How sysclock Enable is Routed in the PMU

3.2.8 Undervoltage Shutdown

In active mode the PMU periodically measures the battery voltage using the ADC from the charger unit. If the

battery is measured to be below the programmable shut-down level (called SYSOFF), the system changes to

OFF mode. This is done via the SHUTDOWN state of the PMU state machine. (see chapter switch OFF)

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3.2.9 Silent Reset

WDT-reset and software-reset shall happen silently to ending customer: SIM card and interfaces have to stay

powered and not reset by neither WDT-reset or C166s SRST instruction. To allow this, some LDO settings and

some registers (as e.g. USIM_pad control register) are reset only by system-reset (HW-reset or power-on reset)

Figure 3.2.5 PMU Reset

3.2.10 PMU Clock

During the first startup (for example plugging in a battery) a PMU internal oscillator is used for generation of

the PMU clock (pmu_clock). The frequency is slightly above 32 kHz (typ. 50 kHz) to be out of the audio band

also for worst case devices. After first startup the software shall enable the 32 kHz crystal oscillator. It is not

possible to use the 32 kHz oscillator during first startup, because the settling time of the oscillator can be

quite long. After the 32 kHz oscillator is running and settled the software shall switch the PMU clock to the 32

kHz clock and disable the internal PMU oscillator for power saving reasons. The 32 kHz oscillator shall never

be disabled after the PMU clock has been switched. The ADC in the charger unit has it’s own oscillator

generating a frequency of about 10 MHz. This oscillator is running during charging and during battery

measurements triggered by the PMU. It is off otherwise.

3. TECHNICAL BRIEF

3.2.11 System Sleep Mode

The sleep mode is controlled by using the VCXO_enable signal (dcxo_en_i) and gsm_sleep_i. These signals are

used to deactivate the HPBG and setting LDO LPMU in the ultra-low-power mode. In addition the DCXO is

switched off by the VCXO_enable signal. The VCXO_enable signal is also used to switch some LDO’s (software

configured) to sleep and/or off mode or to change the output voltages of said LDO’s. The state of the main PMU

state machine is not changed due to VCXO_enable.

3.2.12 DC/DC Pre-Load Register Handling

The DC/DC converter works in different modes. If the mode is switched from PFM to PWM the pulse-width of

the DC/DC converter depends on the current battery voltage (and on the output voltage). The PMU state-

machine knows the battery voltage because of the battery supervision function. Depending on this value it

selects a startup pulse-width for the DC/DC converter out of a register table. (4-values)

3.2.13 Power Down Sequence

Setting bit OFF in the GeneralControl register switches the system into OFF mode. After the turn off event, the

state-machine switches to the SHUTDOWN state. The reset_pmu_n_o signal changes to low, the I/O pads are

isolated using the padisolation_n signal, the LCORE LDO and the SD1 DC/DC converter are switched off, the

LPMU LDO is switched to ultra-low power mode, the DCXO is turned off and the bandgap buffer is disabled.

Before switching OFF the software shall have enabled the 32 kHz oscillator and has switched the PMU clock to

the 32 kHz clock to archive the target OFF current

LGE Internal Use Only

- 29 -

Only for training and service purposes

3. TECHNICAL BRIEF

- 30 -

Only for training and service purposes

LGE Internal Use Only

3.3.1 Internal Block Diagram

3.3 FEM with integrated Power Amplifier Module (SKY77550, U301)

Figure. 3.3.1 SKY77550 FUNCTIONAL BLOCK DIAGRAM

3.3.2 General Description

SKY77550 is a transmit and receive Front-End Module (FEM) with Integrated Power Amplifier Control (iPAC™)

for Dual-band cellular handsets comprising GSM850/900 and DCS1800/PCS1900 operation. Designed in a low

profile, compact form factor, the SKY77550 offers a complete Transmit VCO-to-Antenna and Antenna-to-

Receive SAW filter solution. The FEM also supports Class 12 General Packet Radio Service (GPRS) multi-slot

operation. The module consists of a GSM850/900 PA block and a DCS1800/PCS1900 PA block,

impedancematching circuitry for 50 ohm input and output impedances, Tx harmonics filtering, high linearity

/ low insertion loss RF switch, and a Power Amplifier Control (PAC) block with internal current sense resistor.

The two Heterojunction Bipolar Transistor (HBT) PA blocks, a BiFET PAC and switch control circuit are

fabricated onto a single Gallium Arsenide (GaAs) die. One PA block supports the GSM850/900 bands and the

other PA block supports the DCS1800/PCS1900 bands. Both PA blocks share common power supply pads to

distribute current. The output of each PA block and the outputs to the two receive pads are connected to the

antenna pad through an RF switch. The GaAs die, Switch die and passive components are mounted on a

multi-layer laminate substrate. The assembly is encapsulated with plastic overmold.

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LG A100 Service Manual

Specifications and Main Features

Frequently Asked Questions

User Manual