LG KB770 Service Manual

Service Manual Model : KB770

Internal Use Only

Service Manual

KB770

Date: November, 2008 / 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) .....................................42

3.7 Subsystem(MSM6280) ..............................................44

3.8 Power Block ..............................................................51

3.9 External memory interface .........................................56

3.10 H/W Sub System .....................................................58

3.11 MAIN Features ........................................................74

4.9 Power ON Troubleshooting .......................................103

4.10 Charger Troubleshooting ........................................105

4.11 USB Troubleshooting ..............................................107

4.12 USIM Detect Troubleshooting ..................................108

4.13 Camera Troubleshooting ........................................110

4.14 Keypad Backlight Troubleshooting ...........................112

4.15 LCD Troubleshooting ..............................................114

4.16 Receiver Path ........................................................115

4.17 Headset path.........................................................117

4.18 Speaker phone path ..............................................119

4.19 Main microphone ..................................................121

4.20 Headset microphone ..............................................123

4.21 Vibrator .................................................................125

4.22 Checking DVB-T/H Block( The DVB-T/H function is for

KB770 ) ................................................................126

5. DOWNLOAD & S/W UPGRADE ..................... 131

6. BLOCK DIAGRAM ........................................ 146

7. CIRCUIT DIAGRAM ...................................... 157

8. BGA PIN MAP ..............................................167

9. PCB LAYOUT ...............................................171

10. CALIBRATION ............................................177

10.1 USAGE OF HOT-KIMCHI .........................................177

4. TROUBLE SHOOTING ..................................... 79

4.1 RF Component Description .........................................79

4.2 WCDMA RF Signal Path .............................................80

4.3 GSM RF Signal Path ..................................................81

4.4 Checking VCTCXO Block ............................................82

4.5 Checking Front-End Module Block ..............................85

4.6 Checking WCDMA Block ............................................87

4.7 Checking GSM Block .................................................94

4.8 Checking Bluetooth Block ........................................100

11. EXPLODED VIEW & REPLACEMENT

PART LIST ................................................. 181

11.1 EXPLODED VIEW ...................................................181

11.2 Replacement Parts ................................................183

11.3 Accessory .............................................................207

- 3 -

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.

- 5 -

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.

- 6 -

Only for training and service purposes

2. PERFORMANCE

2.1 System Overview

Item Specification

Shape GSM900/1800/1900 and WCDMA bar type Handset

Size 108 X 54.5 X 18.3 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)

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

2. PERFORMANCE

(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

- 7 -

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

100k~1GHz -39dBm

MS allocated

Channel

1G~12.75GHz -33dBm

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

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

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

Idle Mode

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

- 8 -

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

Frequency Error

Under Multipath and

Interference

Condition

Idle

Mode

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

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

–

Intermodulation product should

be Less than 55dB below the

level of Wanted signal

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

TolerancePower

control

Power

Toleranc

15 13 ±3 10 10 ±4

16 11 ±5 11 8 ±4

17 9 ±5 12 6 ±4

18 7 ±5 13 4 ±4

19 5 ±5 14 2 ±5

15 0 ±5

9 Burst timing Mask IN Mask IN

- 10 -

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

4 Inner Loop Power control in uplink

5 Minimum Output Power -50dBm(3.84MHz)

Out-of-synchronization handling of output

power

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

Class 4 : +21dBm(±2dB)

Adjust output(TPC command)

cmd 1dB 2dB 3dB

+0.5/1.5 +1/3

+1.5/4.5

-0.5/+0.5 -0.5/+0.5 -

0.5/+0.5

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

-1

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

7 Transmit OFF Power -56dBm(3.84MHz)

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

±25us

9 Change of TFC

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

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

12 Spectrum emission Mask

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

- 11 -

LGE Internal Use Only

2. PERFORMANCE

13 Adjacent Channel Leakage Ratio(ACLR)

Spurious Emissions

(*:additional requirement)

15 Transmit Intermodulation

16 Error Vector Magnitude (EVM)

33dB@5MHz, ACP>-50dBm

43dB@10MHz, ACP>-50dBm

-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

-31dBc@5MHz,Interferer -40dBc

-41dBc@10MHz, Interferer -40dBc

17.5%(>-20dBm)

(@12.2K, 1DPDCH+1DPCCH)

17 Transmit OFF Power

-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)

Adjacent

Channel

Rejection

4 Intermodulation Rejection

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

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

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

Wanted Signal :-98dBm

1st interferer:-44dBm

2nd interferer:-45dBm

Wanted Signal :-96dBm

1st interferer:-44dBm

2nd interferer:-44dBm

- 12 -

Only for training and service purposes

2. PERFORMANCE

Blocking Response

(TCH/FS Class II, RBER)

Wanted Signal :-101dBm

Unwanted : Depend on

Frequency

Wanted Signal :-101dBm

Unwanted : Depend on

Frequency

4) Receiver - WCDMA Mode

No Item Specification

1 Reference Sensitivity Level -106.7 dBm(3.84 MHz)

-25dBm(3.84MHz)

2 Maximum Input Level

3 Adjacent Channel Selectivity (ACS)

4 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)

5 Out-band Blocking

6 Spurious Response

7 Intermodulation Characteristic

8 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

- 13 -

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

Under 3.5 mA

(Paging=5period)

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

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

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 3.77 ± 0.05V

Bar 3 → 2 3.77 ± 0.05V

Bar 2 → 1 3.67 ± 0.05V

Bar 1 → Empty 3.50 ± 0.05V

Low Voltage,

Warning message + Blinking

Power off 3.25 ± 0.05V

- 14 -

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

3.50 ± 0.05V

Only for training and service purposes

2. PERFORMANCE

2.7 Sound Pressure Level

No Test Item Specification

1 Sending Loudness Rating (SLR)

Nor

2 Receiving Loudness Rating (RLR)

Max

3 Side Tone Masking Rating (STMR) Min 17 dB

4 Echo Loss (EL) Min 40 dB

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

Nor Under -58 dBPA

6 Idle Noise-Receiving (INR)

Max Under -58 dBPA

7 Sending Loudness Rating (SLR)

Nor

8 Receiving Loudness Rating (RLR)

Max

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

Nor Under -45 dBPA

12 Idle Noise-Receiving (INR)

Max Under -40 dBPA

± 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

Max Under -62 dBm

Headset

- 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

3. TECHNICAL BRIEF

3.1 General Description

The KB770 supports UMTS-2100, GSM-900, DCS-1800, and PCS-1900 based GSM/GPRS/EDGE/UMTS. All receivers and the UMTS transmitter use the radioOne[1] 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-IF

• UMTS Cell + PCS with Rx

diversity

• Quad-band EDGE/GPRS

IMT primary only

Primary

Antenna

• Simultaneous-GPS

• EDGE/GPRS Tx/Rx and

WCDMA Tx are on the RTR6275 IC

• One high-band WCDMA Rx is

on the RTR6275 IC

• Two PLLs on the RTR6275 IC:

– One for EDGE/GPRS Tx/Rx

and WCDMA Tx

– One for WCDMA Rx

• GPS pre-LNA within RFR

• UHF VCOs within RFR

• Two PLLs within RFR:

– One for primary and

diversity receive path

– One for GPS

• LO buffers, etc. within RFR

• No RTR/RFR LO interfaces

– No External VCOs

H-B PF

L-B PF

U800/ 8 50

U1900

U2100

G850 Rx

G900 Rx

G1800 Rx

G1900 Rx

Power

Detect or

LPF

BPF

Quadrature Upconver t er

BPF

Quadrature

LO Generat ion & Distribution

Quadrature

Downconver ter

Upconver t er

Quadrature

Downconverter

BPF

U2100

LNA

Pre-

LNA

RFR6500

Rx BP F

Quadrature

Downconverter

LO Gener ation & Distribution

retl

pool

i f

CDMA VCOs

PCS BPF

Cell BPF

GPS BPF

Quad

D’convert

LPF

DAC_REF

LPF

F ref RFR6275_TCXO

F ref

PLL #1

LPF & DC Correction

VCO

RTR6275

LPF & DC Correction

sO/IlatigiD

sl o

r t noc

ctls

F ref

PLL #2

VCO

RFR6 500_TCXO

LO Gen & Dist

Quad

D’convert

Diversity

Rx VCO

F ref

ctls

LPF

Primary path

LPF

Jammer detec t

LPF

Secondary path

LPF

PLL1

F ref

sO/Ilat

slortn

giD

GPS VCO

F ref

PLL0

Quad

D’convert

Diversity

Rx VCO

LO Gen & Dist

M S M

VDDM

/08 7

002

FPL

VDDM

SBI(s)

and other

status

control

MSM_ TC X O

retlif

pool

da p

dap

niahcy

s relpuoc

s iad

UMTS Diver sity

GPS Antenna

U850

Tx BPF

U2100 Tx BPF

SAW

U1900 Tx BPF

G850 &

G900

Rx BPFs

G1800 &

G1900 Rx BPFs

GPS

U800/ 850

U1900

Rx BPF

Cell

Rx BPF

PCS

Rx BPF

Figure 3.1 Block diagram of RF part

- 17 -

LGE Internal Use Only

3. TECHNICAL BRIEF

A generic, high-level functional block diagram of KB770 is shown in Figure 3.1. One antenna collects base station forward link signals and radiates handset reverse link signals. The antenna connects with

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

KB770 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 KB770’s receiver functions are split between the three RFICs as follows:

■ 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 three

RX saw filters (EGSM-900, DCS-1800 and PCS-1900). The antenna switch module allows multiple

operating bands and modes to share the same antenna. In KB770, a common antenna connects to one of

six paths: 1) UMTS-2100 Rx/Tx, 2) EGSM-900 Rx, 3) EGSM-900 Tx, 4) DCS-1800 Rx, and 5) DCS-1800,

PCS-1900 Tx(High Band Tx’s share the same path), 6) PCS-1900 Rx. UMTS operation requires

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

separates receive and transmit signals. 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 GSM900, DCS1800, and PCS1900 receiver inputs of RTR6275 are connected directly to the transceiver front-end circuits(filters and antenna switch module). 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 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 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.

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Only for training and service purposes

3. TECHNICAL BRIEF

Figure 3.2.1 RTR6275 RX feature

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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 EGSM900 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.

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Only for training and service purposes

3. TECHNICAL BRIEF

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.

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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LGE Internal Use Only

3. TECHNICAL BRIEF

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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Only for training and service purposes

3. TECHNICAL BRIEF

Figure 3.3.2 RTR6275 IC functional block diagram

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LGE Internal Use Only

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 transmitter, and all four GSM band receivers and transmitters including: GSM900, DCS1800, and PCS1900. The second synthesizer (PLL2) provides the LO for the UMTS 2100 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 off-chip 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(FL100 : 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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Only for training and service purposes

3. TECHNICAL BRIEF

3.5.2 UMTS Dupexer(FL102 : ACMD-7602)

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 KB770 typical losses : UMTS2100_ Tx = 1.6 dB, UMTS2100_ Rx = 2.0 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 Txband 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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LGE Internal Use Only

3. TECHNICAL BRIEF

3.5.3 UMTS PAM(U102 : AWT6279R)

The UMTS PA output power is monitored by power detector circuits (U101 : RTR6275) .

This detector voltage can be used for transmitter calibration and monitor to meet RF system specification.

WCDMA_2100

4 3

ACMD-7602

PGND RX ANT

C148

FL102

1 2

C146

R122

3.3p

C151

2.7nH

OUT

COU

TER

51R124

RX_WCDMA_2100

C155 DNI

HDET

L120

C156

1.2p

6.8nH

C153 15p

LDC151G9520Q-359

U103

C147

100p

VEN

GND1

VMODE1

GND2

RFOUT

VMODE2

RFIN

GND3

VBATT

VCC

110

PGND

U102AWT6279R

+VPWR

C143

10u

FL103

EFCH1950TDF1

C154

100p

PA_ON

C159

100p

2G13

L122 NA

PA_R1

C158 100p

L121

2.2nH

R123

C157 DNI

WCDMA_2100_TX_OU

Figure 3.5.3 UMTS PAM, Duplexer, Coupler

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Only for training and service purposes

3. TECHNICAL BRIEF

3.5.4 VCTCXO(X100 : 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(U503 : 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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LGE Internal Use Only

3. TECHNICAL BRIEF

- 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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Only for training and service purposes

3. TECHNICAL BRIEF

Figure 3.5.5.1 PM6650 Interface with MSM

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LGE Internal Use Only

+ 177 hidden pages

LG KB770 Service Manual

Specifications and Main Features

Frequently Asked Questions

User Manual