LG KT615 Service Manual

Date: October, 2008 / Issue 1.0

Service Manual

Model : KT615

Service Manual

KT615

Internal Use Only

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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 ..................................9

2.4 Current Consumption.............................16

2.5 RSSI BAR ..............................................16

2.6 Battery BAR ...........................................16

2.7 Sound Pressure Level............................17

2.8 Charging ................................................18

3. TECHNICAL BRIEF ........................19

3.1 GENERAL DESCRIPTION ....................19

3.2 GSM MODE ...........................................21

3.3 UMTS MODE .........................................24

3.4 GPS MODE............................................27

3.5 LO GENERATION and

DISTRIBUTION CIRCUIT ......................28

3.6 OFF-CHIP RF COMPONENTS .............29

3.7 Digital Baseband

(Stn8810 / MSM6280)............................32

3.8 Hardware Architecture ...........................34

3.9 Subsystem of STn8810..........................37

3.10 Hardware Peripheral system of

Stn8810................................................40

3.11 Subsystem of MSM6280......................46

3.12 External memory interface ...................48

3.13 Hardware sub system of MSM6280.....50

3.14 Audio and sound ..................................62

3.15 Camera interface .................................69

3.16 Bluetooth..............................................77

3.17 Main Features ......................................78

3.18 Main Component..................................79

4. TROUBLE SHOOTING ...................86

4.1 RF Component.......................................86

4.2 SIGNAL PATH .......................................88

4.3 Checking TCXO Block ...........................91

4.4 Checking Ant. Switch Module Block ......93

4.5 Checking WCDMA Block .......................95

4.6 Checking GSM Block ...........................106

4.7 Power on trouble..................................113

4.8 USB trouble..........................................115

4.9 SIM detect trouble................................116

4.10 Key sense trouble ..............................117

4.11 Keypad backlight trouble....................119

4.12 Folder on/off trouble...........................121

4.13 Micro SD trouble ................................123

4.14 Charging trouble ................................125

4.15 Audio trouble......................................127

4.16 Camera trouble ..................................140

4.17 Main LCD trouble ...............................146

4.18 Bluetooth trouble................................149

5. DOWNLOAD .................................151

5.1 COM PORT setting method when

using USB Download ...........................151

5.2 How to KT615 Download .....................154

6. BLOCK DIAGRAM ........................157

7. CIRCUIT DIAGRAM ......................165

8. BGA IC PIN CHECK......................177

9. PCB LAYOUT................................187

10. CALIBRATION & RF AUTO TEST

(HOT KIMCHI) .............................195

10.1 Usage of Hot-Kimchi ..........................195

11. TEST MODE ................................198

12. EXPLODED VIEW &

REPLACEMENT PART LIST ......201

12.1 EXPLODED VIEW .............................201

12.2 Replacement Parts

<Mechanic component>.....................207

<Main component> ............................211

12.3 Accessory ..........................................233

Table Of Contents

LGE Internal Use Only

- 4 -

LGE Internal Use Only

Only for training and service purposes

LGE Internal Use Only

- 5 -

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.

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.

1. INTRODUCTION

LGE Internal Use Only

Only for training and service purposes

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.

1. INTRODUCTION

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LGE Internal Use Only

2. PERFORMANCE

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2.1 System Overview

2. PERFORMANCE

Item Specification

Shape GSM900/1800/1900 and WCDMA Communicator Handset

Size 108.9 X 53.9 X 17.2 mm

Weight 127 g (with 950mAh Battery)

Power 3.7V normal, 950 mAh Li-Polymer

Talk Time Over 170 min (TX = 12dBm,Low Power mode)

(with 950mAh) Over 180 min (TX Level = Max)

Standby Time Over 220 hours (DRX = 1.28)

(with 950mAh) Over 290 hours (Paging Period = 5)

Antenna Internal type and Antenna

LCD TFT LCD ( Main : 2.4’, 320 x 240, Sub :1.45” 160X64 )

LCD Backlight LED Back Light (Main, Sub)

Camera Dual Camera ; 2 Mega pixel (CMOS), VGA Camera (CMOS)

Vibrator Yes (Cylinder Type)

LED Indicator No

MIC Yes

Receiver Yes

Earphone Jack Yes

Connectivity Bluetooth, USB

Volume Key Push Type (+, -)

External Memory Micro-SD

I/O Connect 18 Pin

LGE Internal Use Only

Only for training and service purposes

2.2 Usable environment

2.2.1 Environment

2.2.2 Environment (Accessory)

* CLA : 12~24V(DC).

2. PERFORMANCE

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Item Specification

Voltage 3.7 V(Typ), [Shut Down : 3.22 V]

Operation Temp -20 ~ +60 °C

Storage Temp -20 ~ +70 °C

Humidity 85 % (Max)

Reference Spec. Min Typ. Max Unit

TA Power Available power 100 220 240 Vac

LGE Internal Use Only

2. PERFORMANCE

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2.3 Radio Performance

2.3.1 Transmitter - GSM Mode

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

No Item GSM DCS & PCS

1 Conducted MS allocated 100k~1GHz -39dBm 9k ~ 1GHz -39dBm

Spurious Channel 1G~[A]MHz -33dBm

Emission 1G~12.75GHz -33dBm [A]M~[B]MHz -39dBm

[B]M~12.75GHz -33dBm

Idle Mode 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

2 Radiated MS allocated 30M ~ 1GHz -36dBm 30M~1GHz 36dBm

Spurious Channel 1G~[A]MHz -30dBm

Emission 1G ~ 4GHz -30dBm [A]M~[B]MHz -36dBm

[B]M~4GHz -30dBm

Idle Mode 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

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

LGE Internal Use Only

Only for training and service purposes

2. PERFORMANCE

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No Item GSM DCS & PCS

3 Frequency Error ± 0.1ppm ± 0.1ppm

4 Phase Error ± 5(RMS) ± 5(RMS)

± 20(PEAK) ± 20(PEAK)

5 Frequency Error 3dB below reference sensitivity 3dB below reference sensitivity

Under Multipath and RA250 : ± 200Hz RA250: ± 250Hz

Interference Condition HT100 : ± 100Hz HT100: ± 250Hz

TU50 : ± 100Hz TU50: ± 150Hz

TU3 : ± 150Hz TU1.5: ± 200Hz

6 Output RF Due to 0 ~ 100kHz +0.5dB 0 ~ 100kHz +0.5dB

Spectrum modulation 200kHz -30dB 200kHz -30dB

250kHz -33dB 250kHz -33dB

400kHz -60dB 400kHz -60dB

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

1800 ~ 3000kHz -63dB 1800 ~ 6000kHz -65dB

3000 ~ 6000kHz -65dB ≥ 6000kHz -73dB

≥ 6000kHz -71dB

Due to 400kHz -19dB 400kHz -22dB

Switching 600kHz -21dB 600kHz -24dB

transient 1200kHz -21dB 1200kHz -24dB

1800kHz -24dB 1800kHz -27dB

7 Intermodulation attenuation - Frequency offset 800kHz

Intermodulation product should

be Less than 55dB below the

level of Wanted signal

LGE Internal Use Only

2. PERFORMANCE

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No Item GSM DCS & PCS

8 Transmitter Output Power Level Power Toler. Level Power Toler.

533 ±3030 ±3

631 ±3128 ±3

729 ±3226 ±3

827 ±3324 ±3

925 ±3422 ±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

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

LGE Internal Use Only

Only for training and service purposes

2. PERFORMANCE

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2.3.2 Transmitter - WCDMA Mode

No Item Specification

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

Class 4 : +21dBm( ± 2dB)

2 Frequency Error ± 0.1ppm

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

4 Inner Loop Power control in uplink 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

5 Out-band Blocking -50dBm(3.84MHz)

6 Out-of-synchronization handling of output power 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

9 Change of TFC ± 25us

Power varies according to the data rate DTX :

DPCH off (minimize interference between UE)

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

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

12 Spectrum emission Mask -35-15*(∆f-2.5)dBc@∆f=2.5~3.5MHz,30k

-35-1*(∆f-3.5)dBc@∆f=3.5~7.5MHz,1M -39-

10*(∆f-7.5)dBc@∆f=7.5~8.5MHz,1M

-49dBc@∆f=8.5~12.5MHz,1M

13 Adjacent Channel Leakage Ratio(ACLR) 33dB@5MHz, ACP>-50dBm

43dB@10MHz, ACP>-50dBm

LGE Internal Use Only

2. PERFORMANCE

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No Item Specification

14 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 -31dBc@5MHz,Interferer -40dBc

-41dBc@10MHz, Interferer -40dBc

16 Error Vector Magnitude (EVM) 17.5%(>-20dBm)

(@12.2K, 1DPDCH+1DPCCH)

17 Transmit OFF Power -15dB@SF=4.768Kbps, Multi-code

transmission

- 14 -

2. PERFORMANCE

LGE Internal Use Only

Only for training and service purposes

2.3.3 Receiver - GSM Mode

No Item GSM DCS & PCS

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

2 Co-Channel Rejection (TCH/FS C/Ic=7dB Storage -30 ~ +85

Class II, RBER, TU high/FH)

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

Channel

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

4 Intermodulation Rejection Wanted Signal :-98dBm Wanted Signal :-96dBm

1st interferer :-44dBm 1st interferer :-44dBm

2nd interferer :-45dBm 2nd interferer :-44dBm

5 Blocking Response Wanted Signal :-101dBm Wanted Signal :-101dBm

(TCH/FS Class , RBER) Unwanted : Depend on Unwanted : Depend on

Frequency Frequency

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2. PERFORMANCE

LGE Internal Use Only

2.3.4 Receiver - WCDMA Mode

No Item Specification

1 Reference Sensitivity Level -106.7 dBm(3.84 MHz)

2 Maximum Input Level -25dBm(3.84MHz)

-44dBm/3.84MHz(DPCH_Ec)

UE@+20dBm output power(Class3)

3 Adjacent Channel Selectivity (ACS) 33dB

UE@+20dBm output power(Class3)

4In-band Blocking -56dBm/3.84MHz@10MHz

UE@+20dBm output power(Class3)

-44dBm/3.84MHz@15MHz

UE@+20dBm output power(Class3)

5 Out-band Blocking -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)

6 Spurious Response -44dBm CW

UE@+20dBm output power(Class3)

7 Intermodulation Characteristic -46dBm CW@10MHz

-46dBm/3.84MHz@20MHz

UE@+20dBm output power(Class3)

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

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

-60dBm@f=1850 MHz ≤ f ≤ 1910 MHz,

3.84M BW

-60dBm@f=824 MHz ≤ f ≤ 849 MHz, 3.84M BW

- 16 -

2. PERFORMANCE

LGE Internal Use Only

Only for training and service purposes

2.4 Current Consumption

(Stand by and Voice Call Test Condition : LCD backlight Off) (VT Test Condition : Speaker off, LCD backlight On,0dBm Tx power)

2.5 RSSI BAR

2.6 Battery BAR

Stand by(BT Off condition) Voice Call VT

WCDMA Under 4.32 mA Under 335 mA Under 569mA

(DRX=1.28) (Tx=10dBm) (Tx=10dBm

-Low power) -Low power)

GSM Under 4.32 mA Under 380 mA

(Paging=5period) (Tx=Max power)

Level Change CDMA GSM

7 → 6 -86 ± 2dBm -82 ± 2dBm

6 → 5 -90 ± 2dBm -86 ± 2dBm

5 → 4 -94 ± 2dBm -90 ± 2dBm

4 → 3 -98 ± 2dBm -94 ± 2dBm

3 → 2 -102 ± 2dBm -98 ± 2dBm

2 → 1 -106 ± 2dBm -102 ± 2dBm

1 → 0 -110 ± 2dBm -106 ± 2dBm

Indication Standby

Bar 7 3.96 ± 0.05V

Bar 7 → 6 3.95 ± 0.05V

Bar 6 → 5 3.86 ± 0.05V

Bar 5 → 4 3.78 ± 0.05V

Bar 4 → 3 3.74 ± 0.05V

Bar 3 → 2 3.69 ± 0.05V

Bar 2 → 1 3.63 ± 0.05V

Bar 1 → Empty 3.50 ± 0.05V

Low Voltage, 3.63,3.50 ± 0.05V (Stand-by) / 3.63, 3.50 ± 0.05V (Talk) Warning message + tone Bar 2 → 1 / Bar 1 → Empty

Power Off 3.20 ± 0.05V

- 17 -

2. PERFORMANCE

LGE Internal Use Only

2.7 Sound Pressure Level

No Test Item Specification

1 Sending Loudness Rating (SLR) 8 ± 3 dB

2 Receiving Loudness Rating (RLR) Nor -4 ± 3 dB

Max -15 ± 3 dB

3 Side Tone Masking Rating (STMR) Min 17 dB

4 Echo Loss (EL) Min 40 dB

5 Sending Distortion (SD) Refer to Table 30.3

6 Receiving Distortion (RD) Refer to Table 30.4

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

8 Idle Noise-Receiving (INR) Nor Under -47 dBPA

Max Under -36 dBPA

9 Sending Loudness Rating (SLR) 8 ± 3 dB

10 Receiving Loudness Rating (RLR) Nor -1 ± 3 dB

Max -12 ± 3 dB

11 Side Tone Masking Rating (STMR) Min 25 dB

12 Echo Loss (EL) Min 40 dB

13 Sending Distortion (SD) Refer to Table 30.3

14 Receiving Distortion (RD) Refer to Table 30.4

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

16 Idle Noise-Receiving (INR) 16 Nor Under -45 dBPA

Max Under -40 dBPA

17 TDMA Noise Max -62 dBm

-. 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)

Headset

MS and

Headset

- 18 -

2. PERFORMANCE

LGE Internal Use Only

Only for training and service purposes

2.8 Charging

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

• Maximum Charging Voltage : 4.2 V

• Maximum Charging Current : 650mA

• Normal Battery Capacity : 950 mAh

• Charger Voltage : 4.8V

• Charging Time : Max 3 h (Except time trickle charging)

• Full charging indication current (charging icon stop current) : 60mA

• Low battery POP UP : 3.48V

• Low battery alarm interval : Idle - 3 min, Dedicated - 1min

• Cut-off voltage : 3.22V

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3. TECHNICAL BRIEF

LGE Internal Use Only

3.1 GENERAL DESCRIPTION

The KT615 supports UMTS-2100, GSM-900, GSM-1800, and GSM-1900 based GSM/GPRS/EDGE/UMTS. All receivers and the UMTS transmitter use the radioOne1Zero-IF architecture to eliminate intermediate frequencies, directly converting signals between RF and baseband. The quad-band GSM transmitters use a baseband-to-IF upconversion followed by an offset phase-locked loop that translates the GMSK-modulated or 8-PSK-modulated signal to RF.

A generic, high-level functional block diagram of KT615 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 SKY77519(EDGE PAM+ASM). The UMTS receive paths each include an LNA, an RF band-pass filter, and a downconverter that translate the signal directly from RFto-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.

[Fig. 3.1] Block diagram of RF part

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

LGE Internal Use Only

Only for training and service purposes

3. TECHNICAL BRIEF

- 20 -

For the transmit chains, the RTR6285 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 RTR6285 IC outputs deliver fairly high-level RF signals that are first filtered by Tx SAWs and then amplified by their respective UMTS PAs.

In the GSM receive path, the received RF signals are applied through their bandpass filters and downconverted directly to baseband in the RTR6285 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

KT615 power supply voltages are managed and regulated by the PM6658 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.

LGE Internal Use Only

3. TECHNICAL BRIEF

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3.2 GSM MODE

3.2.1 GSM RECEIVER

The GSM-900, GSM-1800, and GSM-1900 receiver inputs of RTR6285 are connected directly to the transceiver front-end circuits(filters and antenna switch module). GSM-900, GSM-1800, and GSM1900 receiver inputs use differential configurations to improve common-mode rejection and secondorder non-linearity performance as shown in Figure 3-2. The balance between the complementary signals is critical and must be maintained from the RF filter outputs all the way into the IC pins

[Figure 3-2] GSM Receiver Inputs Topologies

LGE Internal Use Only

Only for training and service purposes

3. TECHNICAL BRIEF

- 22 -

Since GSM-900, GSM-1800, and GSM-1900 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 GSM-900, GSM-1800, and GSM-1900 receive signals are routed to the RTR6285 through band selection filters and matching networks that transform singleended 50-Ω sources to differential impedances optimized for gain and noise figure.

The RTR input uses a differential configuration to improve second-order intermodulation and common mode rejection performance. The RTR6285 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 as shown in Figure 3-4.

LGE Internal Use Only

3. TECHNICAL BRIEF

- 23 -

3.2.2 GSM TRANSMITTER

The RTR6285 transmitter outputs(HB_RF_OUT1 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 as shown in Figure 3-3.

The RTR6285 IC is able to support GSM 900 and GSM 1800/1900 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.

[Figure 3-3] GSM Transmitter Outputs Topologies

LGE Internal Use Only

Only for training and service purposes

3. TECHNICAL BRIEF

- 24 -

3.3 UMTS MODE

3.3.1 UMTS RECEIVER

The UMTS duplexer receiver output is routed to LNA circuits within the RTR6285 device as shown in Figure 3-4. The UMTS Rx input is provided with an on-chip LNA that amplifies the signal before a second stage filter that provides differential downconverter as shown in Figure 3-5. 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 RTR6285 is downconverting GSM signals and on when the UMTS is operating.

[Figure 3-4] UMTS Receiver Inputs Topologies

LGE Internal Use Only

3. TECHNICAL BRIEF

- 25 -

3.3.2 UMTS 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 upconverter 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 RTR6285 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 RTR6285 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 RTR6285 IC design achieves this without allowing FVCO to equal FRF.

The RTR6285 IC is able to support UMTS 2100/1900/1800/1700 and 850 mode transmitting. This design guideline shows only UMTS 2100 applications.

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3. TECHNICAL BRIEF

LGE Internal Use Only

Only for training and service purposes

WCDMA_2100_TX

WCDMA_2100_RX

[Figure 3.5] RTR6285 IC Functional Block Diagram

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3. TECHNICAL BRIEF

3.4 GPS MODE

3.4.1 GPS RECEIVER

The GPS receicer input employs a single-ended connection realized by this pin. The GPS input is routed from the GPS antenna switch, through a bandpass filter and then an impedance transformer circuit that optimally matches the impedance looking into the GPS LNA. The impedance transformer circuit topology is shown in Figure 3-6.

LGE Internal Use Only

[Figure 3.6] GPS Input Network Topology

LGE Internal Use Only

Only for training and service purposes

3. TECHNICAL BRIEF

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3.5 LO GENERATION and DISTRIBUTION CIRCUIT

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, UMTS band and GPS 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 fraction-N synthesizers, including VCOs and loop filters, are integrated within the RTR6285 IC. In addition, the RTR6285 has a third synthesizer used for GPS operation. The first synthesizer (PLL1) in the RTR6285 creates the transceiver Los that support the UMTS transmitter, and all four GSM band receivers and transmitters including:

GSM850, GSM900, GSM1800, and GSM1900. The second synthesizer (PLL2) in the RTR6285 IC provides the LO for the UMTS primary receiver. For the RTR6285 IC only, the second synthesizer also provides the LO for the secondary UMTS receiver.

The third synthesizer (PLL3), only in the RTR6285 IC, provides the LO for the GPS receiver. An external TCXO input signal is required to provide the synthesizer frequency reference to which the PLL is phase and frequency locked. The RTR6285 ICs integrate most of the PLL loop filter components onchip except for three off-chip loop filter-series capacitors, which significantly reduces off-chip component requirement. With the integrated fractional-N PLL synthesizers, the RTR6285 ICs have the advantage of more flexible loop bandwidth control, fast lock time, and lowintegrated phase error.

LGE Internal Use Only

3. TECHNICAL BRIEF

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3.6 OFF-CHIP RF COMPONENTS

3.6.1 ALM-1412(U603:GPS LNA)

The ALM-1412 is an LNA module, with integrated filter, designed for GPS band applications at

1.575GHz. The LNA uses AVAGO Technologies’ proprietary GaAs Enhancement-mode pHEMT process to achieve high gain with very low noise figure and high linearity Noise figure distribution is very tightly controlled. A CMOScompatible shutdown pin is included either for turning the LNA on/off, or for current adjustment. The integrated filter utilizes an Avago Technologies’ leading edge FBAR filter for exceptional rejection at Cell/PCS Band frequencies. The ALM-1412 is useable down to 1V operation. It achieves low noise figure, high gain and linearity even at 1V, making it suitable for use in critical lowpower GPS applications or during low-battery situations.

3.6.2 SKY77519(U601:GSM FEM)

RF Front end consists of antenna, antenna switch module (SKY77519) which includes EDGE PAM. The antenna switch module allows multiple operating bands and modes to share the same antenna. In KT615, a common antenna connects to one of six paths: 1) UMTS-2100 Rx/Tx, 2) GSM-900 Rx, 3) GSM-900 Tx, 4) GSM- 1800 Rx, and 5) GSM-1800, GSM-1900 Tx(High Band Tx’s share the same path), 6) GSM-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. GSM-900, GSM-1800, and GSM-1900 operation is time division duplexed, so only the receiver or transmitter is active at any time and a frequency duplexer is not required. The active connection is MSM-selected by three control lines (GPIO[9], GPIO[10] and GPIO[11]). These GPIOs are programmed to be ANT_SEL0 , ANT_SEL1 and ANT_SEL2 respectively.

LGE Internal Use Only

Only for training and service purposes

3. TECHNICAL BRIEF

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TXEN BS1 BS2

GSM 900 TX LOW LOW HIGH

GSM 1800/GSM 1900 TX LOW HIGH HIGH

GSM 900 RX HIGH HIGH LOW

GSM 1800 RX HIGH HIGH HIGH

GSM 1900 RX HIGH LOW HIGH

WCDMA LOW HIGH LOW

Table 1. Antenna Switch Module Logic

[Figure 3.5] SKY77519 Functional Block Diagram.

LGE Internal Use Only

3. TECHNICAL BRIEF

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3.6.3 W-CDMA POWER AMPLIFIER (U604: ACPM-7381)

The ACPM-7381, a Wide-band Code Division Multiple Access(WCDMA) Power Amplifier(PA), is a fully matched 10-pin surface mount module developed for WCDMA handset applications. This power amplifier module is developed to cover 1920- 1980MHz bandwidth. The ACPM-7381 meets the stringent WCDMA linearity requirements for output power of up to 28dBm. The ACPM-7381 is also developed to meet HSDPA specs.

The ACPM-7381 is designed to enhance the efficiency at low and medium output power range by using 3-mode control scheme with 2 mode control pins. This provides extended talk time. The ACPM-7381 is self contained, incorporating 50ohm input and output matching networks.

3.6.4 W-CDMA DUPLXER (FL605: ACMD-7602)

The ACMD-7602 is a miniature duplexer designed for use in UMTS Band I handsets and enhances the sensitivity and dynamic range of WCDMA receivers by providing more than 53dB attenuation of the transmitted signal at the receiver input and more than 43dB rejection of transmit-generated noise in the receiver band. The ACMD-7602 is designed with FBAR technology, which makes possible ultra-small, high-Q filters at a fraction of their usual size. The excellent power handling capability of the FBAR bulkmode resonators supports the high output power levels needed in handsets while adding virtually no distortion.

[Figure 3.6] ACPM-7381 Functional Block Diagram.

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