LG KB775f Service Manual

Service Manual Model : KB775f

Internal Use Only

Service Manual

KB775f

Date: April, 2009 / Issue 1.0

Table Of Contents

1. INTRODUCTION ...............................................5

1.1 Purpose ......................................................................5

1.2 Regulatory Information .................................................5

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

2.1 System Overview .........................................................7

2.2 Usable environment .....................................................8

2.3 Radio Performance ......................................................8

2.4 Current Consumption .................................................14

2.5 RSSI BAR ..................................................................14

2.6 Battery BAR ..............................................................14

2.7 Sound Pressure Level ................................................15

2.8 Charging ...................................................................16

3. TECHNICAL BRIEF .........................................17

3.1 General Description ...................................................17

3.2 GSM Mode ................................................................19

3.3 UMTS Mode ..............................................................23

3.4 LO generation and distribution circuits ........................26

3.5 Off-chip RF Components ............................................26

3.6 Digital Baseband (MSM6280) .....................................40

3.7 Subsystem(MSM6280) ..............................................42

3.8 Power Block ..............................................................49

3.9 External memory interface .........................................54

3.10 H/W Sub System .....................................................56

3.11 MAIN Features ........................................................72

4.15 Keypad Backlight Troubleshooting ...........................113

4.16 LCD Troubleshooting ..............................................115

4.17 Receiver Path ........................................................116

4.18 Headset path.........................................................118

4.17 Speaker phone path ..............................................120

4.18 Main microphone ..................................................122

4.19 Headset microphone ..............................................124

4.20 Vibrator .................................................................126

4.21 ISDB-T Circuit diagram, ISN7200 & ISDB-T RF ........127

5. DOWNLOAD .................................................129

5.1 Introduction .............................................................129

5.2 Downloading Procedure ...........................................130

5.3 Troubleshooting Download Errors ..............................146

5.4 Caution ...................................................................153

6. BLOCK DIAGRAM ........................................ 154

7. CIRCUIT DIAGRAM ...................................... 163

8. BGA Pin Map .............................................. 175

9. PCB LAYOUT ...............................................179

10. Hotkimchi .................................................187

10.1 Usage of Hot-Kimchi ..............................................187

11. TEST MODE ............................................... 190

4. TROUBLE SHOOTING ..................................... 77

4.1 RF Component ..........................................................77

4.2 Component Description ..............................................80

4.3 WCDMA RF Signal Path .............................................81

4.4 GSM RF Signal Path ..................................................82

4.5 Checking VCTCXO Block ............................................83

4.6 Checking Front-End Module Block ..............................86

4.7 Checking WCDMA Block ............................................88

4.8 Checking GSM Block .................................................95

4.9 Checking Bluetooth Block ........................................100

4.10 Power ON Troubleshooting .....................................103

4.11 Charger Troubleshooting ........................................105

4.12 USB Troubleshooting ..............................................107

4.13 USIM Detect Troubleshooting ..................................109

4.14 Camera Troubleshooting ........................................111

12. EXPLODED VIEW & REPLACEMENT

PART LIST ................................................ 195

12.1 EXPLODED VIEW ...................................................195

12.2 Replacement Parts ................................................197

12.3 Accessory ............................................................. 221

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LGE Internal Use Only

- 4 -

Only for training and service purposes

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 phones or compatibility with the net work, the

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

appropriate steps to maintain telephone service.

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LGE Internal Use Only

1. INTRODUCTION

D. Maintenance Limitations

Maintenance limitations on the phones 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.

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

A 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.

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Only for training and service purposes

2. PERFORMANCE

2.1 System Overview

Item Specification

Shape GSM850/900/1800/1900 and WCDMA 850/2100 bar type Handset

Size 111 X 54.8 X 11.9 mm

Weight 93 g (with 1000mAh Battery)

Power 4.0V normal, 1000 mAh(Li-ion) inner-pack

Talk Time Over 180 min (WCDMA, Tx=12 dBm, Voice)

(with 1000mAh) Over 180 min (GSM, Tx=Max, Voice)

2. PERFORMANCE

Standby Time Over 250 Hrs (WCDMA, DRX=1.28)

(with 1000mAh) Over 320 Hrs (GSM, Paging period=5)

Antenna Internal type

LCD 400 x 240 pixel (TFT)

LCD Backlight White LED Back Light

Camera 3.0 Mega (CMOS) / VGA (CMOS).

Vibrator Yes

LED Indicator No

MIC Yes

Receiver Yes

Earphone Jack Yes (18 pin)

Connectivity Bluetooth, USB

Volume Key Push Type(+, -)

External Memory Trans-Flash

I/O Connect 18 Pin

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LGE Internal Use Only

2. PERFORMANCE

2.2 Usable environment

1) Environment

Item Specification

Voltage 4.0 V(Typ), 3.28 V(Min), [Shut Down : 3.25 V]

Operation Temp -20 ~ +60 °C

Storage Temp -20 ~ +70 °C

Humidity 85 % (Max)

2) Environment (Accessory)

Reference Spec. Min Typ. Max Unit

TA Power Available power 100 220 240 Vac

* CLA : 12 ~ 24 V(DC)

2.3 Radio Performance

1) Transmitter - GSM Mode

No Item GSM DCS & PCS

9k ~ 1GHz -39dBm

1G~[A]MHz -33dBm

[A]M~[B]MHz -39dBm

[B]M~12.75GHz -33dBm

Conducted

Spurious

Emission

MS allocated

Channel

Idle Mode

100k~1GHz -39dBm

1G~12.75GHz -33dBm

100k~880MHz -60dBm 100k~880MHz -60dBm

880M~915MHz -62dBm 880M~915MHz -62dBm

915M~1GHz -60dBm 915M~1GHz -60dBm

1G~[A]MHz -50dBm 1G~[A]MHz -50dBm

[A]M~[B]MHz -56dBm [A]M~[B]MHz -56dBm

[B]M~12.5GHz -50dBm [B]M~12.5GHz -50dBm

* In case of DCS : [A] -> 1710, [B] -> 1785 * In case of PCS : [A] -> 1850, [B] -> 1910

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Only for training and service purposes

2. PERFORMANCE

No Item GSM DCS & PCS

allocated

Channel

Radiated

Spurious

Emission

3 Frequency Error ±0.1ppm ±0.1ppm

4 Phase Error

Under Multipath and

Interference Condition

Idle Mode

Frequency Error

30M ~ 1GHz -36dBm

1G ~ 4GHz -30dBm

30M ~ 880MHz -57dBm 30M~880MHz -57dBm

880M ~ 915MHz -59dBm 880M~915MHz -59dBm

915M~1GHz -57dBm 915M~1GHz -57dBm

1G~[A]MHz -47dBm 1G~[A]MHz -47dBm

[A]M~[B]MHz -53dBm [A]M~[B]MHz -53dBm

[B]M~4GHz -47dBm [B]M~4GHz -47dBm

±5(RMS) ±5(RMS)

±20(PEAK) ±20(PEAK)

3dB below reference sensitivity 3dB below reference sensitivity

RA250 : ±200Hz RA250: ±250Hz

HT100 : ±100Hz HT100: ±250Hz

TU50 : ±100Hz TU50: ±150Hz

TU3 : ±150Hz TU1.5: ±200Hz

30M~1GHz -36dBm

1G~[A]MHz -30dBm

[A]M~[B]MHz -36dBm

[B]M~4GHz -30dBm

0 ~ 100kHz +0.5dB 0 ~ 100kHz +0.5dB

200kHz -30dB 200kHz -30dB

Due to

modulati

Output RF

Spectrum

*In case of DCS : [A] -> 1710, [B] -> 1785 * In case of PCS : [A] -> 1850, [B] -> 1910

Due to

Switching

transient

250kHz -33dB 250kHz -33dB

400kHz -60dB 400kHz -60dB

600 ~ 1800kHz -66dB 600 ~ 1800kHz -60dB

1800 ~ 3000kHz -69dB 1800 ~ 6000kHz -65dB

3000 ~ 6000kHz -71dB ≥6000kHz -73dB

≥6000kHz -77dB

400kHz -19dB 400kHz -22dB

600kHz -21dB 600kHz -24dB

1200kHz -21dB 1200kHz -24dB

1800kHz -24dB 1800kHz -27dB

- 9 -

LGE Internal Use Only

2. PERFORMANCE

No Item GSM DCS & PCS

Frequency offset 800kHz

Intermodulation attenuation

8 Transmitter Output Power

Power

control

Level (dBm) (dB) Level (dBm) (dB)

5 33 ±3 0 30 ±3

6 31 ±3 1 28 ±3

7 29 ±3 2 26 ±3

8 27 ±3 3 24 ±3

9 25 ±3 4 22 ±3

10 23 ±3 5 20 ±3

11 21 ±3 6 18 ±3

12 19 ±3 7 16 ±3

13 17 ±3 8 14 ±3

14 15 ±3 9 12 ±4

15 13 ±3 10 10 ±4

–

Power

Tolerance Power

Intermodulation product should

be Less than 55dB below the

level of Wanted signal

control

Power

Toleranc

16 11 ±5 11 8 ±4

17 9 ±5 12 6 ±4

18 7 ±5 13 4 ±4

19 5 ±5 14 2 ±5

9 Burst timing Mask IN Mask IN

- 10 -

15 0 ±5

Only for training and service purposes

2. PERFORMANCE

2) Transmitter – WCDMA Mode

No Item Specification

1 Maximum Output Power

2 Frequency Error ±0.1ppm

3 Open Loop Power control in uplink ±9dB@normal, ±12dB@extreme

Inner Loop Power control in uplink

5 Minimum Output Power -50dBm(3.84MHz)

Out-of-synchronization handling of output

power

7 Transmit OFF Power -56dBm(3.84MHz)

Class3: +24dBm(+1/-3dB)

Class 4 : +21dBm(±2dB)

Adjust output(TPC command)

cmd 1dB 2dB 3dB

+1 +0.5/1.5 +1/3 +1.5/4.5

0 -0.5/+0.5 -0.5/+0.5 -0.5/+0.5

-1 -0.5/-1.5 -1/-3 -1.5/-4.5

Group (10 equel command group)

+1 +8/+12 +16/+24

Qin/Qout : PCCH quality levels

Toff@DPCCH/Ior : -22 -> -28dB

Ton@DPCCH/Ior : -24 -> -18dB

8 Transmit ON/OFF Time Mask ±25us PRACH,CPCH,uplinlk compressed mode

±25us

Change of TFC

10 Power setting in uplink compressed ±3dB(after 14slots transmission gap)

11 Occupied Bandwidth(OBW) 5MHz(99%)

Spectrum emission Mask

13 Adjacent Channel Leakage Ratio(ACLR)

Power varies according to the data rate DTX : DPCH

off

(minimize interference between UE)

-35-15*(Δf-2.5)dBc@Δf=2.5~3.5MHz,30k

-35-1*(Δf-3.5)dBc@Δf=3.5~7.5MHz,1M

-39-10*(Δf-7.5)dBc@Δf=7.5~8.5MHz,1M

-49dBc@Δf=8.5~12.5MHz,1M

33dB@5MHz, ACP>-50dBm

43dB@10MHz, ACP>-50dBm

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LGE Internal Use Only

2. PERFORMANCE

Spurious Emissions

(*:additional requirement)

-36dBm@f=9~150KHz, 1K BW

-36dBm@f=50KHz~30MHz, 10K BW

-36dBm@f=30MHz~1000MHz, 100K BW

-30dBm@f=1~12.5GHz,1M BW

(*)-41dBm@f=1893.5~1919.6MHz, 300K

(*)-67dBm@f=925~935MHz, 100K BW

(*)-79dBm@f=935~960MHz, 100K BW

(*)-71dBm@f=1805~1880MHz, 100K BW

15 Transmit Intermodulation

16 Error Vector Magnitude (EVM)

17 Transmit OFF Power

-31dBc@5MHz,Interferer -40dBc

-41dBc@10MHz, Interferer -40dBc

17.5%(>-20dBm)

(@12.2K, 1DPDCH+1DPCCH)

-15dB@SF=4.768Kbps,

Multi-code transmission

3) Receiver - GSM Mode

No Item GSM DCS & PCS

1 Sensitivity (TCH/FS Class II) -105dBm -105dBm

Co-Channel Rejection (TCH/FS Class

II, RBER, TU high/FH)

C/Ic=7dB Storage -30 ~ +85

Adjacent

Channel

Rejection

Intermodulation Rejection

Blocking Response

(TCH/FS Class II, RBER)

200kHz C/Ia1=-12dB C/Ia1=-12dB

400kHz C/Ia2=-44dB C/Ia2=-44dB

Wanted Signal :-98dBm

1st interferer:-44dBm

2nd interferer:-45dBm

Wanted Signal :-101dBm

Unwanted : Depend on

Frequency

Wanted Signal :-96dBm

1st interferer:-44dBm

2nd interferer:-44dBm

Wanted Signal :-101dBm

Unwanted : Depend on

Frequency

- 12 -

Only for training and service purposes

2. PERFORMANCE

4) Receiver - WCDMA Mode

No Item Specification

1 Reference Sensitivity Level -106.7 dBm(3.84 MHz)

-25dBm(3.84MHz)

Maximum Input Level

3 Adjacent Channel Selectivity (ACS)

In-band Blocking

-44dBm/3.84MHz(DPCH_Ec)

UE@+20dBm output power(Class3)

33dB

UE@+20dBm output power(Class3)

-56dBm/3.84MHz@10MHz

UE@+20dBm output power(Class3)

-44dBm/3.84MHz@15MHz

UE@+20dBm output power(Class3)

Out-band Blocking

6 Spurious Response

Intermodulation Characteristic

Spurious Emissions

-44dBm/3.84MHz@f=2050~2095 and

2185~2230MHz

UE@+20dBm output power(Class3)

-30dBm/3.84MHz@f=2025~2050 and

2230~2255MHz

UE@+20dBm output power(Class3)

-15dBm/3.84MHz@f=1~2025 and

2255~12500MHz

UE@+20dBm output power(Class3)

-44dBm CW

UE@+20dBm output power(Class3)

-46dBm CW@10MHz

-46dBm/3.84MHz@20MHz

UE@+20dBm output power(Class3)

-57dBm@f=9KHz~1GHz, 100K BW

-47dBm@f=1~12.5GHz, 1M BW

-60dBm@f=1920MHz~1980MHz, 3.84M BW

-60dBm@f=2110MHz~2170MHz, 3.84M BW

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LGE Internal Use Only

2. PERFORMANCE

2.4 Current Consumption

Stand by(BT Off condition) Voice Call VT

WCDMA

Under 3.5 mA

(DRX=1.28)

Under 320 mA

(Tx=12dBm)

Under 430mA

(Tx=0dBm)

GSM

(Stand by and Voice Call Test Condition : LCD backlight Off)

(VT Test Condition : Speaker off, LCD backlight On)

Under 3.5 mA

(Paging=5period)

Under 300 mA

(Tx=Max)

2.5 RSSI BAR

Level Change WCDMA GSM

BAR 7 >= -91 dBm >= -92 dBm

BAR 7 → 6,5 -93 ± 2 dBm -94 ± 2 dBm

BAR 6,5 → 4 -105 ± 2 dBm -98 ± 2 dBm

BAR 4 → 3,2 -110 ± 2 dBm -102 ± 2 dBm

BAR 3,2 → 1 -112 ± 2 dBm -105 ± 2 dBm

BAR 1 → 0 -114 ± 2 dBm -107 ± 2 dBm

2.6 Battery BAR

Indication Standby

Bar 3 Over 3.72 ± 0.05V

Bar 3 → 2 3.72 ± 0.05V

Bar 2 → 1 3.60 ± 0.05V

Bar 1 → Empty 3.45 ± 0.05V

Low Voltage,

Warning message + Blinking

Power off 3.25 ± 0.05V

- 14 -

[Interval: 3min(Stand by)/1min(talk)]

3.45 ± 0.05V

Only for training and service purposes

2. PERFORMANCE

2.7 Sound Pressure Level

No Test Item Specification

1 Sending Loudness Rating (SLR)

2 Receiving Loudness Rating (RLR)

3 Side Tone Masking Rating (STMR) Min 17 dB

4 Echo Loss (EL) Min 40 dB

5 Idle Noise-Sending (INS) Max -64 dBm0p

6 Idle Noise-Receiving (INR)

7 Sending Loudness Rating (SLR)

8 Receiving Loudness Rating (RLR)

9 Side Tone Masking Rating (STMR) Min 25 dB

Headset

10 Echo Loss (EL) Min 40 dB

11 Idle Noise-Sending (INS) Max -55 dBm0p

12 Idle Noise-Receiving (INR)

Nor

Max

Nor Under -58 dBPA

Max Under -58 dBPA

Nor

Max

Nor Under -45 dBPA

Max Under -40 dBPA

± 3 dB

2±3 dB

-8

-6

-13

±3 dB

TDMA Noise

-. GSM : Power Level : 5

DCS/PCS : Power Level : 0

(Cell Power : -90 ~ -105 dBm)

-. Acoustic (Max Vol.)

MS/Headset SLR : 8 3dB

MS/Headset RLR : -15 3dB / -12dB

(SLR/RLR : Mid-value setting)

MS and

Headset

Max Under -62 dBm

- 15 -

LGE Internal Use Only

2. PERFORMANCE

2.8 Charging

• Charging Method : CC & CV (Constant Current and Constant Voltage)

• Maximum Charging Voltage : 4.2 V

• Maximum Charging Current : 600 mA

• Normal Battery Capacity : 1000 mAh

• Charging Time : Max 3 hours (except for trickle charging time)

• Full charging indication current (charging icon stop current) : 80mA

• Cut-off voltage : 3.2 V

- 16 -

Only for training and service purposes

2. SYSTEM SPECIFICATION

3. TECHNICAL BRIEF

3.1 General Description

The KB775 supports UMTS-2100,UMTS-850, GSM-850,GSM-900, DCS-1800, and PCS-1900 based GSM/GPRS/EDGE/UMTS. All receivers and the UMTS transmitter use the radioOne[1] IF architecture to eliminate intermediate frequencies, directly converting signals between RF and baseband. The quad-band GSM transmitters use a baseband-to-IF up-conversion followed by an offset phase-locked loop that translates the GMSK-modulated or 8-PSK-modulated signal to RF.

Zero-

Figure 3.1 Block diagram of RF part

A generic, high-level functional block diagram of KB775 is shown in Figure 3.1. One antenna collects base station forward link signals and radiates handset reverse link signals. The antenna connects with

[1] QUALCOMM’s branded chipset that implements a Zero-IF radio architecture.

- 17 -

LGE Internal Use Only

3. TECHNICAL BRIEF

receive and transmit paths through a FEM(Front End Module)

The UMTS receive paths each include an LNA, an RF band-pass filter, and a downconverter that

translate the signal directly from RF-to-baseband using radioOne ZIF techniques. The RFIC’s Rx

analog baseband outputs, for the receive chains, connect to the MSM IC. The UMTS and GSM Rx

baseband outputs share the same inputs to the MSM IC.

For the transmit chains, the RTR6275 IC directly translates the Tx baseband signals (from the

MSM device) to an RF signal using an internal LO generated by integrated on-chip PLL and VCO.

The RTR6275 IC outputs deliver fairly high-level RF signals that are first filtered by Tx SAWs and

then amplified by their respective UMTS PAs. The high- and low-band UMTS RF transmit signals

emerge from the RTR6275 transceiver.

In the GSM receive path, the received RF signals are applied through their band-pass filters and

down-converted directly to baseband in the RTR6275 transceiver IC. These baseband outputs are

shared with the UMTS receiver and routed to the MSM IC for further signal processing.

The GSM/EDGE transmit path employs one stage of up-conversion and, in order to improve

efficiency, is divided into phase and amplitude components to produce an open-loop Polar topology:

1. The on-chip quadrature up-converter translates the GMSK-modulated signal or 8-PSK

modulated signal, to a constant envelope phase signal at RF;

2. The amplitude-modulated (AM) component is applied to the ramping control pin of Polar power

amplifier from a DAC within the MSM

KB775 power supply voltages are managed and regulated by the PM6650 Power Management IC.

This versatile device integrates all wireless handset power management, general housekeeping,

and user interface support functions into a single mixed signal IC. It monitors and controls the

external power source and coordinates battery recharging while maintaining the handset supply

voltages using low dropout, programmable regulators.

The device’s general housekeeping functions include an ADC and analog multiplexer circuit for

monitoring on-chip voltage sources, charging status, and current flow, as well as user-defined off-

chip variables such as temperature, RF output power, and battery ID. Various oscillator, clock, and

counter circuits support IC and higher-level handset functions. Key parameters such as under-

voltage lockout and crystal oscillator signal presence are monitored to protect against detrimental

conditions.

- 18 -

Only for training and service purposes

3. TECHNICAL BRIEF

3.2 GSM Mode

3.2.1 GSM Receiver

The Dual-mode KB775’s receiver functions are split between the three RFICs as follows:

■ GSM-850,EGSM-900(GSM900), DCS-1800, and PCS-1900 modes use the RTR6275 IC only.

Each mode has independent front-end circuits and down-converters, but they share common

baseband circuits (with only one mode active at a time). All receiver control functions are beginning

with SBI

RF Front end consists of antenna, antenna switch module (LMSP4LMA-573TEMP) which includes

four RX saw filters (GSM-850,EGSM-900, DCS-1800 and PCS-1900). The antenna switch module

allows multiple operating bands and modes to share the same antenna. In KB775, a common

antenna connects to one of eight paths: 1) GSM900/GMS850 TX, 2)DCS/PCS TX , 3)GSM850 RX,

4)GSM900 RX, 5)DCS RX, 6)PCS RX, 7)UMTS 850, 8)UMTS 2100. UMTS operation requires

simultaneous reception and transmission, so the UMTS Rx/Tx connection is routed to a duplexer that

separates receive and transmit signals. GSM850,GSM900, DCS1800, and PCS1900 operation is

time division duplexed, so only the receiver or transmitter is active at any time and a frequency

duplexer is not required.

-controlled parameters.

Table 3.2.1 Antenna Switch Module Control logic

2 The RFIC operating modes and circuit parameters are MSM-controlled through the proprietary 3-line Serial Bus Interface (SBI). The Application Programming Interface (API) is used to implement SBI commands. The API is documented in AMSS Software – please see applicable AMSS Software documentation for details.

- 19 -

LGE Internal Use Only

3. TECHNICAL BRIEF

The GSM850,GSM900, DCS1800, and PCS1900 receiver inputs of RTR6275 are connected directly to the transceiver front-end circuits(filters and antenna switch module). GSM850,GSM900, DCS1800, and PCS1900 receiver inputs use differential configurations to improve common-mode rejection and second-order non-linearity performance. The balance between the complementary signals is critical and must be maintained from the RF filter outputs all the way into the IC pins.

Since GSM850,GSM900, DCS1800, and PCS1900 signals are time-division duplex (the handset can only receive or transmit at one time), switches are used to separate Rx and Tx signals in place of frequency duplexers – this is accomplished in the switch module.

The GSM850,GSM900, DCS1800, and PCS1900 receive signals are routed to the RTR6275 through band selection filters and matching networks that transform single-ended 50W sources to differential impedances optimized for gain and noise figure. The RTR input uses a differential configuration to improve second-order inter-modulation and common mode rejection performance. The RTR6275 input stages include MSM-controlled gain adjustments that maximize receiver dynamic range.

The amplifier outputs drive the RF ports of the quadrature RF-to-baseband downconverters. The downconverted baseband outputs are multiplexed and routed to lowpass filters (one I and one Q) having passband and stopband characteristics suitable for GMSK or 8-PSK processing. These filter circuits include DC offset corrections. The filter outputs are buffered and passed on to the MSM6280 IC for further processing.

- 20 -

Only for training and service purposes

3. TECHNICAL BRIEF

Figure 3.2.1 RTR6275 RX featur e

- 21 -

LGE Internal Use Only

3. TECHNICAL BRIEF

3.2.2 GSM Transmitter

The RTR6275 transmitter outputs (HB_RF_OUT2 and LB_RF_OUT1) include on-chip output matching

inductors. 50ohm output impedance is achieved by adding a series capacitor at the output pins. The

capacitor value may be optimized for specific applications and PCB characteristics based on pass-band

symmetry about the band center frequency. The suggested circuit is shown in Fig.3.2.2

Figure 3.2.2 GSM Transmitter matching

The RTR6275 IC is able to support GSM850/GSM900 and DCS1800/PCS1900 mode transmitting. This design guideline shows a tri-band GSM application.

Both high-band and low band outputs are followed by resistive pads to ensure that the load Presented to the outputs remains close to 50ohm. The low-band GSM Tx path also includes a Tx-band SAW filter to remove noise-spurious components and noise that would be amplified by the PA and appear in the GSM Rx band.

- 22 -

Only for training and service purposes

3. TECHNICAL BRIEF

UMTS_850_RX

3.3 UMTS Mode

3.3.1 Receiver

The UMTS duplexer receiver output is routed to LNA circuits within the RFR6275 device. UMTS LNA circuits(one for low-band UMTS and one for high-ban UMTS path) separated from all other receive functions contained within the RFR6275 receiver IC to improve mixer LO to RF isolation a critical parameter in the ZIF architecture. Isolation is further improved using high-reverse isolation circuits into the LNA designes. The LNA gains are stepped via API control. The IC operating mode and LNA bias currents reautomatically adjusted via software to minimize DC power consumption.

[Figure 3.3.1] RFR6275 IC functional bloc k di ag ra m

The UMTS Rx input is provided with an on-chip LNA that amplifies the signal before a second stage filter that provides differential downconverter. This second stage input is configured differentially to optimize second-order intermodulation and common mode rejection performance. The gain of the UMTS frontend amplifier and the UMTS second stage differential amplifier are adjustable, under MSM control, to extend the dynamic range of the receivers. The second stage UMTS Rx amplifiers drive the RF ports of the quadrature RF-to-baseband downconverters. The downconverted UMTS Rx baseband outputs are routed to lowpass filters having passband and stopband characteristics suitable for UMTS Rx processing. These filter circuits allow DC offset corrections, and their differential outputs are buffered to interface shared with GSM Rx to the MSM IC. The UMTS baseband outputs are turned off when the RTR6275 is downconverting GSM signals and on when the UMTS is operating.

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3.3.2 Transmitter

The UMTS Tx path begins with differential baseband signals (I and Q) from the MSM device.

These analog input signals are amplified, filtered, and applied to the quadrature up-converter mixers.

The up-converter output is amplified by multiple variable gain stages that provide transmit AGC control.

The AGC output is filtered and applied to the driver amplifier; this output stage includes an integrated

matching inductor that simplifies the external matching network to a single series capacitor to achieve the desired 50-Ω interface.

The RTR6275 UMTS output is routed to its power amplifier through a bandpass filter, and delivers fairly

high-level signals that are filtered and applied to the PA. Transmit power is delivered from the duplexer

to the antenna through the switch module.

The transceiver LO synthesizer is contained within the RTR6275 IC with the exception of the off-chip

loop filter components and the VC-TCXO. This provides a simplified design for multimode applications.

The PLL circuits include a reference divider, phase detector, charge pump, feedback divider, and digital

logic generator.

UMTS Tx. Using only PLL1, the LO generation and distribution circuits create the necessary LO signals

for nine different frequency converters. The UMTS transmitter also employs the ZIF architecture to

translate the signal directly from baseband to RF. This requires FLO to equal FRF, and the RTR6275 IC

design achieves this without allowing FVCO to equal FRF.

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UMTS_850_TX

Figure 3.3.2 RTR6275 IC functional block diagr am

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3. TECHNICAL BRIEF

3.4 LO generation and distribution circuits

The integrated LO generation and distribution circuits are driven by internal VCOs to support various modes to yield highly flexible quadrature LO outputs that drive all GSM/EDGE and UMTS band upconverters and downconverters; with the help of these LO generation and distribution circuits, true zero-IF architecture is employed in all GSM and UMTS band receivers and transmitters to translate the signal directly from RF to baseband and from baseband to RF. Two fully functional fractional-N synthesizers, including VCOs and loop filters, are integrated within the RTR6275 IC. The first synthesizer (PLL1) creates the transceiver LOs that support the UMTS 2100/1900/1800 transmitter, and all four GSM band receivers and transmitters including: GSM 850, GSM 900, GSM 1800, and GSM 1900. The second synthesizer (PLL2) provides the LO for the UMTS 2100/1900/1800 receiver. An external TCXO input signal is required to provide the synthesizer frequency reference to which the PLL is phase and frequency locked. The RTR6275 IC integrates most of PLL loop filter components on-chip except two off-chip loop filter series capacitors, and significantly reduces offchip component requirement. With the integrated fractional-N PLL synthesizers, the RTR6275 has the advantages of more flexible loop bandwidth control, fast lock time, and low-integrated phase error

3.5 Off-chip RF Components

3.5.1 Front-End Module(FL1000 : LMSP4LMA-573TEMP)

This equipment uses a single antenna to support all handset operating modes, with an antenna switch module select the operating frequency and band. UMTS operation requires simultaneous reception and transmission, so the UMTS Rx/Tx connection is routed to a duplexer that separates receive and transmit signals. The active connection is MSM-selected by three control lines (GPIO[9], GPIO[10], GPIO[11], GPIO[12]). These GPIOs are programmed to be ANT_SEL0, ANT_SEL1, ANT_SEL2, ANT_SEL3 respectively.

Table 3.5.1 Antenna Switch Module Control logic

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3.5.2 UMTS Dupexer(U1003,FL1003)

A UMTS duplexer splits a single operating band into receive and transmit paths. Important performance requirements include;

Insertion loss, this component is also in the receive and transmit paths ; In the KB775 typical losses : UMTS2100_ Tx = 1.5 dB, UMTS2100_ Rx = 1.8 dB

UMTS850 _ Tx = 1.8 dB, UMTS2100_ Rx = 2.2 dB

Out-of-band rejection or attenuation, the duplexer provides input selectivity for the receiver, output filtering for the transmitter, and isolation between the two. Rejection levels for both paths are specified over a number of frequency ranges. Two Tx-to-Rx isolation levels are critical to receiver performance:

Rx-band isolation, the transmitter is specified for out-of-band noise falling into the Rx band. This noise leaks from the transmit path into the receive path, and must be limited to avoid degrading receiver sensitivity. The required Rx-band isolation depends on the PA out of-band noise levels and Rx-band losses between the PA and LNA. Minimum duplexer Rx band isolation value is about 46.7 dB.

Tx-band isolation, the transmit channel power also leaks into the receiver. In this case, the leakage is outside the receiver passband but at a relatively high level. It combines with Rx band jammers to create cross-modulation products that fall in-band to desensitize the receiver. The required Tx-band isolation depends on the PA channel power and Tx-band losses between the PA and LNA. Minimum duplexer Tx-band isolation value is about 51.7dB.

Passband ripple, the loss of this fairly narrowband device is not flat across its passband. Passband ripple increases the receive or transmit insertion loss at specific frequencies, creating performance variations across the band.s channels, and should be controlled.

Return loss, minimize mismatch losses with typical return losses of 10 dB or more (VSWR <2:1).

Power handling, high power levels in the transmit path must be accommodated without degraded performance. The specified level depends on the operating band class and mobile station class (per the applicable standard), as well as circuit losses and antenna EIRP. Several duplexer characteristics depend upon its source and load impedances. QUALCOMM strongly recommends an isolator be used between the UMTS PA and duplexer to assure proper performance.

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3.5.3 UMTS PAM(U1004 :RF5184)

UMTS850/UMTS 2100 Power Amplifier Module

The RF5184 is a high-power, high-efficiency linear amplifier module specifically designed for 3V handheld systems. The device is manufactured on an advanced third generation GaAs HBT process, and was designed for use as the final RF amplifier in UMTS handheld digital cellular equipment, spread-spectrum systems, and other applications in the 824 MHz to 915 MHz band (Band V and VIII) and 1850 MHz to 1980 MHz band (Band II and I). The RF5184 is assembled in a 24 pin, 4mm * 4mm, QFN package.

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3. TECHNICAL BRIEF

3.5.4 VCTCXO(X1000 : TG-5010LH_19_2M_75A)

The Voltage Controlled Temperature Compensated Crystal Oscillator (VCTCXO) provides the reference frequency for all RFIC synthesizers as well as clock generation functions within the MSM6280 IC. The oscillator frequency is controlled by the MSM6280 IC.s TRK_LO_ADJ pulse density modulated signal in the same manner as the transmit gain control TX_AGC_ADJ. A two-pole RC lowpass filter is recommended on this control line.

The PM6650 IC controls the handset power-up sequence, including a special VCTCXO warm-up interval before other circuits are turned on. This warm-up interval (as well as other TCXO controller functions) is enabled by the MSM TCXO_EN line . The PM6650 IC VREG_TCXO regulated output voltage is used to power the VCTCXO and is enabled before most other regulated outputs. Any GSM mode power control circuits within the MSM6280 IC require a reference voltage for proper operation and sufficient accuracy. Connecting the PM6650 IC REF_OUT directly to the MSM6275 IC GSM_PA_PWR_CTL_REF provides this reference. This sensitive analog signal needs a 0.1 μF low frequency filter near to MSM side, and isolate from digital logic and clock traces with ground on both sides, plus ground above and below if routed on internal layers

3.5.5 PMIC Functional Block Diagram(U601 : PM6650-3P)

 Input power management

- Valid external supply attachment and removal detection

- Supports unregulated (closed-loop) external charger supplies and USB supplies as input power sources

- Supports lithium-ion main batteries

- Trickle, constant current, constant voltage, and pulsed charging of the main battery

- Supports coin cell backup battery (including charging)

- Battery voltage detectors with programmable thresholds

- VDD collapse protection

- Charger current regulation and real-time monitoring for over-current protection

- Charger transistor protection by power limit control

- Control drivers for two external pass transistors and one external battery MOSFET—MOSFET is optional

- Voltage, current, and power control loops

-Automated recovery from sudden momentary power loss

 Output voltage regulation

- One boost (step-up) switched-mode power supply (SMPS) for driving white LEDs and hosting USBOTG

- Three buck (step-down) switched-mode power supplies that efficiently generate MSMC, MSME, and PA (or second MSMC) supply voltages

- Supports dynamic voltage scaling (DVS) for MSMC and PA

- Eleven low dropout regulator circuits with programmable output voltages, implemented using three different current ratings: 300 mA (two), 150 mA (six), and 50 mA (three). These can be used to power MSMA, MSMP, RFRX1, RFRX2, RFTX, SYNT, TCXO, WLAN, MMC, USB, and RUIM circuits.

- All regulators can be individually enabled/disabled for power savings

- Low power mode available on MSMA and MSMP regulators

- All regulated outputs are derived from a common bandgap reference—close tracking

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- Integrated handset-level housekeeping functions reduces external parts count, size, cost

- Analog multiplexer selects from 8 internal and up to 18 external inputs

- Multiplexer output’s offset and gain are adjusted, increasing the effective ADC resolution

- Adjusted multiplexer output is buffered and routed to an MSM device ADC

- Dual oscillators – 32.768 kHz off-chip crystal and on-chip RC assures MSM device sleep clock

- Crystal oscillator detector and automated switch-over upon lost oscillation

- Real time clock for tracking time and generating associated alarms

- On-chip adjustments minimize crystal oscillator frequency errors

- Circuits control TCXO warm-up and synchronize, deglitch, and buffer the TCXO signal

- TCXO buffer control for optimal QPH/catnap timing

-Three-stage over-temperature protection (smart thermal control)

 Integrated handset-level user interfaces

- Four programmable current sinks recommended as keypad backlight, LCD backlight, camera flash,

and general-purpose drivers

- Vibration motor driver programmable from 1.2 to 3.1V in 100 mV increments

-Speaker driver with programmable gain, turn-on time, and muting; differential operation (drives external 8 Ω speakers with volume controlled 500 mW)

 IC-level interfaces

- MSM device-compatible 3-line SBI for efficient initialization, status, and control

- Supports the MSM device’s interrupt processing with an internal interrupt manager

- Many functions monitored and reported through real-time and interrupt status signals

- Dedicated circuits for controlled power-on sequencing, including the MSM device’s reset signal

- Several events continuously monitored for triggering power-on/power-off sequences

- Supports and orchestrates soft resets

- USB-OTG transceiver for full-speed (12 Mb/s) and low speed (1.5 Mb/s) interfacing of the MSM

device to computers as a USB peripheral, or connecting the MSM device to other peripherals

-RUIM level translators enable MSM device interfacing with external modules

 Twelve multi-purpose pins that can be configured as digital or analog I/Os, bi-directional I/Os, or

current sinks. Default functions support the RUIM level translators, power-on circuits, analog

multiplexer inputs, an LED driver, and a reference voltage buffer.

 Highly integrated functionality in a small package – 84-pin BCCS with a large center slug for electrical

ground, mechanical stability, and thermal relief

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Figure 3.5.5.1 PM6650 Interface with MSM

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LG KB775f Service Manual

Specifications and Main Features

Frequently Asked Questions

User Manual