LG CU320 Service Manual

Date: March, 2006 / Issue 1.0

Service Manual

Model : CU320

Service Manual

CU320

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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 ..................................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.............................................20

3.2.1 GSM Receiver .................................20

3.2.2 GSM Transmitter..............................22

3.3 WCDMA Mode .......................................23

3.3.1 Receiver...........................................23

3.3.2 Transmitter.......................................26

3.4 LO Phase-locked Loop ..........................27

3.4.1 UMTS Rx PLL (PLL2) ......................27

3.4.2 Transceiver PLL (PLL1)...................28

3.5 Off-chip RF Components .......................29

3.5.1 Antenna switch module....................29

3.5.2 UMTS duplexer................................29

3.5.3 UMTS Power Amplifier

(U1016, U1006) ...............................30

3.5.4 Thermistor........................................31

3.5.5 UMTS transmit power detector ........32

3.5.6 GSM/GPRS/EDGE Power amplifier 33

3.5.7 GSM transmit VCO ..........................34

3.5.8 UMTS Rx RF filter ...........................34

3.5.9 GSM band Rx RF filter ....................35

3.5.10 VCTCXO........................................35

3.5.11 UMTS Rx VCO...............................36

3.5.12 Bluetooth........................................36

3. BB Technical Description............. 38

3.6 Digital Baseband(DBB/MSM6275).........38

3.6.1 General Description .........................38

3.7 Hardware Architecture ...........................39

3.7.1 Block Diagram(MSM6275)...............40

3.8 Subsystem(MSM6275) ..........................41

3.8.1 ARM Microprocessor Subsystem.....41

3.8.2 UMTS Subsystem............................41

3.8.3 GSM Subsystem..............................41

3.8.4 RF Interface .....................................42

3.8.5 Serial Bus Interface(SBI) .................42

3.8.6 Wideband CODEC...........................42

3.8.7 Vocoder Subsystem.........................42

3.8.8 ARM Microprocessor subsystem .....42

3.8.9 Mode Select and JTAG Interfaces...43

3.8.10 General-Purpose Input/Output

Interface .........................................43

3.8.11 UART .............................................43

3.8.12 USB ...............................................43

3.9 Power Block ...........................................44

3.10 External memory interface ...................49

3.11 H/W Sub System..................................50

3.11.1 RF Interface ...................................50

3.11.2 MSM Sub System ..........................52

3.11.3 HKADC(House Keeping ADC).......54

3.11.4 Key Pad .........................................55

3.11.5 Camera Interface ...........................57

3.11.6 Slide ON/OFF Operation ...............59

3.11.7 Keypad Light..................................60

3.11.8 Camera Flash Light .......................61

3.11.9 LCD Module...................................62

3.11.10 Display & LCD FPC Interface ......63

3.11.11 Audio and Sound .........................64

Table Of Contents

Table Of Contents

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3.12 Main Features ......................................75

3.12.1 LG-CU320 Main features...............75

3.12.2 CU320 Main Component ...............76

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

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

4.2 SIGNAL PATH_WCDMA RF .................83

4.3 Checking VCXO Block ...........................85

4.4 Checking Ant. SW Module Block ...........88

4.5 Checking WCDMA Block .......................90

4.5.1 Checking TX POWER of WCDMA

1900MHz..........................................90

4.5.2 Checking TX POWER of WCDMA

850MHz............................................92

4.5.3 Checking WCDMA PAM Control Block94

4.5.4 Check RF Rx Level..........................95

4.6 Checking GSM Block .............................97

4.6.1 Checking VCO Block .......................98

4.6.2 Checking Ant. SW Module.............100

4.6.3 Checking RF Tx level.....................100

4.6.4 Checking PAM Block .....................102

4.6.5 Checking RF Rx Block...................103

4.7 Power ON Troubleshooting..................105

4.8 Charger Troubleshooting .....................108

4.9 USB Troubleshooting...........................111

4.10 SIM Detect Troubleshooting ..............113

4.11 Key Sense Troubleshooting...............114

4.12 Camera Troubleshooting ...................115

4.13 Keypad Backlight Troubleshooting ....116

4.14 Slide ON/OFF Troubleshooting..........117

4.15 Camera Flash Troubleshooting..........118

4.16 Main LCD Troubleshooting ................119

4.17 Audio Trouble Shooting .....................121

5. DOWNLOAD .................................132

5.1 Introduction ..........................................132

5.2 Downloading procedure .......................132

5.3 Troubleshooting download errors ........139

5.4 Caution.................................................154

6. BLOCK DIAGRAM ........................145

6.1 GSM & WCDMA RF Block...................145

6.2 Interface Diagram ..............................147

7. Circuit Diagram ............................151

8. pcb layout .....................................158

9. Calibration & Auto test Program

Manual...........................................163

9.1 Configuration of HOT KIMCHI .............163

9.1.1 Configuration of directory...............163

9.1.2 Setup file (Info_Db.txt) ...................164

9.1.3 Items of setup file...........................165

9.1.4 Examples of setup file....................166

9.2 How to use Hot Kimchi.........................167

9.3 HOT KIMCHI Start Example ................168

10. EXPLODED VIEW &

REPLACEMENT PART LIST ..... 172

10.1 EXPLODED VIEW ............................ 172

10.2 Replacement Parts

<Mechanic component>.................... 175

<Main component> ........................... 179

10.3 Accessory ......................................... 203

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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
network, the telephone company is required to give advanced written notice to the user, allowing the
user to take appropriate steps to maintain telephone service.

D. Maintenance Limitations

Maintenance limitations on 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

1. INTRODUCTION

E. Notice of Radiated Emissions

This model complies with rules regarding radiation and radio frequency emission as defined by local
regulatory agencies. In accordance with these agencies, you may be required to provide information
such as the following to the end user.

F. Pictures

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

G. Interference and Attenuation

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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2. PERFORMANCE

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2.1 System Overview

2. PERFORMANCE

Item Specification

Shape GSM850/1800/1900 and WCDMA Slide Handset

Size 97 X 48 X 24.3mm

Weight 122 g (with Battery)

Power 4.0V normal, 1000 mAh Li-ion

Talk Time

Over 120 min (WCDMA, Voice)

Over 150 min (GSM, Voice)

Stand by Time

Over 250 Hrs (WCDMA, DRX=1.28)

Over 250 Hrs (GSM, Paging period=5)

Antenna Fixed Type (Fixed Screw)

LCD Main 176 X 220 pixel (TFT)

LCD Backlight White LED Back Light

Camera 1.3 Mega pixel (CMOS)

Vibrator Yes (Coin Type)

LED Indicator No

C-MIC Yes

Receiver Yes

Earphone Jack Yes(2.5mm)

Connectivity Bluetooth, USB

Volume Key Push Type(+, -)

External Memory Trans-Flash

I/O Connect 24 Pin

2.2 Usable environment

1) Environment

2) Environment (Accessory)

* CLA : 12 ~ 24 V(DC)

2.3 Radio Performance

1) Transmitter - GSM Mode

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

2. PERFORMANCE

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Item Specification

Voltage 4.0 V(Typ), 3.50 V(Min), [Shut Down : 3.35 V]

Operation Temp -20 ~ +60 °C

Storage Temp -30 ~ +85 °C

Humidity 85 % (Max)

Reference Spec. Min Typ. Max Unit

TA Power Available power 100 110 240 Vac

No Item GSM DCS & PCS

100k~1GHz -39dBm

9k ~ 1GHz -39dBm

MS allocated 1G~[A]MHz -33dBm

Channel

1G~12.75GHz -33dBm

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

Conducted [B]M~12.75GHz -33dBm

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

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

Idle Mode

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. PERFORMANCE

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

No Item GSM DCS & PCS

30M ~ 1GHz -36dBm

30M~1GHz -36dBm

MS allocated 1G~[A]MHz -30dBm

Channel

1G ~ 4GHz -30dBm

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

Radiated [B]M~4GHz -30dBm

2Spurious 30M ~ 880MHz -57dBm 30M~880MHz -57dBm

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

Idle Mode

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

3 Frequency Error ±0.1ppm ±0.1ppm

4 Phase Error

±5(RMS) ±5(RMS)

±20(PEAK) ±20(PEAK)

3dB below reference sensitivity 3dB below reference sensitivity

Frequency Error RA250 : ±200Hz RA250: ±250Hz

5 Under Multipath and HT100 : ±100Hz HT100: ±250Hz

Interference Condition TU50 : ±100Hz TU50: ±150Hz

TU3 : ±150Hz TU1.5: ±200Hz

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

200kHz -30dB 200kHz -30dB

250kHz -33dB 250kHz -33dB

Due to 400kHz -60dB 400kHz -60dB

Output RF

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

6 1800 ~ 3000kHz -69dB 1800 ~ 6000kHz -65dB

Spectrum

3000 ~ 6000kHz -71dB ≥6000kHz -73dB

≥6000kHz -77dB

Due to

400kHz -19dB 400kHz -22dB

Switching

600kHz -21dB 600kHz -24dB

transient

1200kHz -21dB 1200kHz -24dB

1800kHz -24dB 1800kHz -27dB

2. PERFORMANCE

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No Item GSM DCS & PCS

Frequency offset 800kHz

7 Intermodulation attenuation –

Intermodulation product should

be Less than 55dB below the

level of Wanted signal

Power control

Power Tolerance

Power control

Power Tolerance

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

533±3 030±3

631±3 128±3

729±3 226±3

827±3 324±3

925±3 422±3

10 23 ±3 5 20 ±3

8 Transmitter Output Power 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

2. PERFORMANCE

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2) Transmitter - WCDMA Mode

No Item Specification

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

2 Frequency Error ±0.1ppm

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

Adjust output(TPC command)

cmd 1dB 2dB 3dB

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

4 Inner Loop Power control in uplink 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 Minimum Output Power -50dBm(3.84MHz)

Qin/Qout : PCCH quality levels

6 Out-of-synchronization handling of output power 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

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%)

-35-15*(∆f-2.5)dBc@∆f=2.5~3.5MHz,30k

12 Spectrum emission Mask

-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

3)Receiver - GSM Mode

2. PERFORMANCE

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No Item Specification

13 Adjacent Channel Leakage Ratio(ACLR)

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

14

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

(*: additional requirement) (*)-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

No Item GSM DCS & PCS

1

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

2

Co-Channel Rejection

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

(TCH/FS Class II, RBER, TU high/FH)

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

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

Wanted Signal :-98dBm Wanted Signal :-96dBm

4

Intermodulation Rejection 1st interferer:-44dBm 1st interferer:-44dBm

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

5

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

(TCH/FS Class II, RBER)

Unwanted : Depend on Frequency Unwanted : Depend on Frequency

2. PERFORMANCE

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4) Receiver - WCDMA Mode

No Item Specification

1 Reference Sensitivity Level -106.7 dBm(3.84 MHz)

-25dBm(3.84MHz)

2 Maximum Input Level -44dBm/3.84MHz(DPCH_Ec)

UE@+20dBm output power(Class3)

3 Adjacent Channel Selectivity (ACS)

33dB

UE@+20dBm output power(Class3)

-56dBm/3.84MHz@10MHz

4In-band Blocking UE@+20dBm output power(Class3)

-44dBm/3.84MHz@15MHz

UE@+20dBm output power(Class3)

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

2185~2230MHz

UE@+20dBm output power(Class3)

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

5 Out-band Blocking 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)

-46dBm CW@10MHz

7 Intermodulation Characteristic -46dBm/3.84MHz@20MHz

UE@+20dBm output power(Class3)

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

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

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

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

2. PERFORMANCE

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2.4 Current Consumption

(Stand by and Voice Call Test Condition : Bluetooth off, LCD backlight Off)
(VT Test Condition : Speaker off, LCD backlight On)

2.5 RSSI BAR

2.6 Battery BAR

Indication Standby

Bar 4 Over 3.87 ± 0.05V

Bar 4 → 3 3.86 ± 0.05V

Bar 3 → 2 3.74 ± 0.05V

Bar 2 → 1 3.67 ± 0.05V

Bar 1 → Empty 3.58 ± 0.05V

Low Voltage, 3.50 ± 0.05V (Stand-by) / 3.58 ± 0.05V (Talk)

Warning message+ Blinking [Interval : 3min(Stand-by) / 1min(Talk)]

Power Off 3.35 ± 0.05V

Stand by Voice Call VT

WCDMA

Under 8.5 mA Under 450 mA Under 640mA

(DRX=1.28) (Tx=12dBm) (Tx=12dBm)

Under 6.3 mA

(Paging=9period) Under 380 mA

GSM

Under 7.0 mA (Tx=Max)

(@Bluetooth Connected,

Paging=9period)

Level Change WCDMA GSM

BAR 5 → 4 -85 ± 2 dBm -85 ± 2 dBm

BAR 4 → 3 -90 ± 2 dBm -90 ± 2 dBm

BAR 3 → 2 -95 ± 2 dBm -95 ± 2 dBm

BAR 2 → 1 -98 ± 2 dBm -100 ± 2 dBm

BAR 1 → 0 -101 ± 2 dBm -105 ± 2 dBm

2. PERFORMANCE

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2.7 Sound Pressure Level

No Test Item Specification

1 Sending Loudness Rating (SLR) 8 ±3 dB

2 Receiving Loudness Rating (RLR)

Nor -7 ± 3 dB

Max -18 ± 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±3dB

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)

Nor Under -45 dBPA

Max Under -40 dBPA

TDMA Noise

-. GSM : Power Level : 5

DCS/PCS : Power Level : 0

17 (Cell Power : -90 ~ -105 dBm)

-. Acoustic (Max Vol.)

MS/Headset SLR : 8

±

3dB

MS/Headset RLR : -18 ± 3dB / -15dB

(SLR/RLR : Mid-value setting)

MS

Headset

MS and

Headset

Max -62 dBm

2.8 Charging

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

• Maximum Charging Voltage : 4.2 V

• Maximum Charging Current : 800 mA

• Normal Battery Capacity : 1000 mAh

• Charging Time : Max 3.0 hours (except for trickle charging time)

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

• Cut-off voltage : 3.35 V

2. PERFORMANCE

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3. TECHNICAL BRIEF

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3.1 General Description

The CU320 supports UMTS-850 DS-WCDMA,UMTS-1900 DS-WCDMA, GSM-850, DCS-1800, and
PCS-1900 GSM/GPRS/EGPRS. All receivers and the UMTS transmitter use the radioOne1Zero-IF
architecture to eliminate intermediate frequencies, directly converting signals between RF and
baseband. The GSM850, DCS1800 and PCS1900 transmitters use a baseband-to-IF upconversion
followed by an offset phase-locked loop that translates the GMSK-modulated signal to RF.

1

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

3. TECHNICAL BRIEF

Figure 3-1. Block diagram of RF part

A generic, high-level functional block diagram of CU320 is shown in Figure 1-1.
One antenna collects base station forward link signals and radiates handset reverse link signals. The
antenna connects with receive and transmit paths through a switch module (plus a duplexer for UMTS
dual band operation).

The UMTS receive signal is amplified by the RFL6202 LNA then passes through a bandpass filter
before being applied to the RFR6202 Receiver IC. On-chip circuits downconvert the received signal
directly from RF to baseband using radioOne Zero-IF techniques. Generation of the UMTS
downconverter LO is distributed between the RTR6250 (phase-locked loop), the RFR6202 (buffer
amplifiers and LO distribution circuits) and external UHF VCO and loop filter circuits. The RFR6202 IC
outputs analog baseband signals for further processing by the MSM device. This baseband interface is
shared with the RTR6250 GSM850 /DCS/PCS receiver outputs.

GSM850, DCS and PCS receive signals pass through their bandpass filters then are applied to the
RTR6250 IC. Similar to the UMTS path, RTR6250 circuits downconvert the received signals directly
from RF to baseband. The GSM850/DCS/PCS downconverter LO is generated mostly within the
RTR6250 (PLL and distribution functions); the UMTS Rx CH VCO and loop filter are off-chip.
The RTR analog baseband outputs are routed to the MSM6275 IC for further processing (an interface
shared with the RFR).

The UMTS transmit path begins with analog baseband signals from the MSM device that drive the
RTR6250 IC. Integrated PLL and VCO circuits generate the Tx LO used in the quadrature upconverter
that translates baseband signals directly to RF. The RTR6250 output driver stages deliver fairly high­level signals that are filtered and applied to the power amplifiers (PA). The PA output is routed to the
antenna through a duplexer and switch module.

The shared GSM-850, DCS-1800, and PCS-1900 transmit path begins with the same baseband
interface from the MSM6275 IC that is used for the UMTS band. A single GSM850/DCS/PCS
quadrature upconverter translates the GMSK-modulated signal to a convenient intermediate frequency
(IF) that forms one input to an offset phase-locked loop (OPLL). OPLL functions are split between the
RTR6250 IC and off-chip loop filter and dual Tx VCO circuits, and translate the GMSK-modulated
signal to the desired GSM-850, DCS-1800 or PCS-1900 channel frequency. This signal is applied to a
dual power amplifier (only one is active at a time). The enabled path continues with the PA, an
automated power control (APC) circuit that samples the transmit power and adjusts its level, the switch
module (which includes a band-appropriate lowpass filter), and the antenna.

3. TECHNICAL BRIEF

- 18 -

3. TECHNICAL BRIEF

- 19 -

CU320 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 offchip
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 undervoltage lockout
and crystal oscillator signal presence are monitored to protect against detrimental conditions.

3.2 GSM Mode

3.2.1 GSM Receiver

The Dual-mode CU320’s receiver functions are split between the three RFICs as follows:

• UMTS-850,1900 operation uses the RFL6202 LNA and RFR6202 Receiver ICs to implement the
receive signal path, accepting an RF input and delivering analog baseband outputs (I and Q).

• GSM-850, DCS-1800, and PCS-1900 modes both use the RTR6250 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 SBI2-controlled
parameters.

RF Front end consists of antenna, antenna switch module(CXG1198EQ), and three RX saw
filters(GSM, DCS, and PCS). The antenna switch module allows multiple operating bands and modes
to share the same antenna. In CU320, a common antenna connects to one of seven paths: 1) UMTS­850 Rx/Tx, 2) 1) UMTS-1900 Rx/Tx, 3) GSM-850 Rx, 4) GSM-850 Tx, 5) DCS-1800 Rx, and 6) DCS­1800,PCS-1900 Tx(High Band Tx’s share the same path), 7) 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. GSM850, DCS, and PCS operation is time division duplexed,
so only the receiver or transmitter is active at any time and a frequency duplexer is not required.

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.

3. TECHNICAL BRIEF

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IN_A IN_B IN_C

GSM850 TX HIGH HIGH LOW

DCS/PCS TX HIGH LOW LOW

GSM 850 RX LOW LOW HIGH

UMTS 850 HIGH LOW HIGH

DCS RX LOW HIGH LOW

PCS RX LOW HIGH HIGH

UMTS 1900 HIGH HIGH HIGH

Table. Antenna Switch Module Control logic

3. TECHNICAL BRIEF

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The GSM850, DCS, and PCS receiver inputs of RTR6250 are connected directly to the transceiver front­end circuits(filters and antenna switch module). GSM850, DCS, and PCS receiver inputs are similar to the
RFR6202 UMTS Rx input in that they also 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, DCS, and PCS 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, DCS, and PCS receive signals are routed to the RTR6250 through band selection filters
and matching networks that transform single-ended 50-Ω sources to differential impedances optimized for
gain and noise figure. Similar to the RFR, the RTR input uses a differential configuration to improve
second-order inter-modulation and common mode rejection performance. The RTR6250 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 processing. These filter circuits include DC
offset corrections.
The filter outputs are buffered and passed on to the MSM6275 IC for further processing (an interface
shared with the RFR6202 UMTS receiver outputs).

RTR6250 RX feature

3.2.2 GSM Transmitter

The shared GSM Low-band (GSM850) and High-band (DCS1800, PCS1900) transmit path begins with
the baseband inputs from the MSM6275 IC. These differential analog input signals are buffered,
lowpass filtered, corrected for DC offsets then applied to the GSM quadrature upconverter. The
upconverter LO signals are generated from the transceiver VCO signal by the LO distribution and
generation circuits within RTR6250. This upconverter translates the GMSKmodulated signal to a
convenient intermediate frequency (IF) that forms one input to a frequency/phase detector circuit. This
IF signal is the reference input to an offset phase-locked loop (OPLL) circuit as shown in Figure 3.2.2-1.

The feedback path of this OPLL circuit includes a downconversion from the RF output frequency range
to the IF range. The two inputs to this downconversion mixer are formed as follows:

1. The dual Tx VCO output (operating in the desired RF output frequency range) is buffered within the

RTR6250 IC then applied to the mixer RF port.

2. The LO Generation and Distribution circuits that deliver the transmit path.s LO for the baseband-to-IF

upconversion also provides the .offset LO. signal that is applied to the feedback path.s mixer LO port.

The mixer IF port output is the offset feedback signal - the variable input to the frequency/phase

detector circuit. The detector compares its variable input to its reference input and generates an error
signal that is lowpass filtered by the loop filter and applied to the dual Tx VCO tuning port to force the
VCO output in the direction that minimizes errors. As mentioned earlier, the VCO output is connected to
the feedback path thereby creating a closed-loop control system that will force frequency and phase
errors between the variable and reference inputs to zero.

3. TECHNICAL BRIEF

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Figure 3.2.2-1 Offset phase-locked loop interfaces

3. TECHNICAL BRIEF

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The waveform at the dual Tx VCO output is the GMSK-modulated signal centered at the desired GSM
channel frequency. A phase-locked loop circuit is used to translate the GMSK-modulated signal from IF
to RF primarily for two reasons:

1. Phase-locked loops provide a lowpass filter function from the reference input to the VCO output. This
results in a bandpass function centered at the desired channel frequency that provides steep, well­controlled rejection of the out-of-band spectrum.

2. The resulting output bandpass function is virtually unchanged as the transmitter is tuned over
channels spanning the GSM operating band.

The PA is a key component in any transmitter chain and must complement the rest of the transmitter
precisely. For GSM band operation, the closed-loop transmit power control functions add even more
requirements relative to the UMTS PA. In addition to gain control and switching requirements, the usual
RF parameters such as gain, output power level, several output spectrum requirements, and power
supply current are critical. The gain must be sufficient and variable to deliver the desired transmitter
output power given the VCO output level, the subsequent passive devices’ losses, and the control set
point. The maximum and minimum transmitter output power levels depend upon the operating band
class and mobile station class per the applicable standard. Transmitter timing requirements and inband
and out-of-band emissions, all dominated by the PA, are also specified by the applicable standard.

The active dual Tx VCO output is applied to the dual power amplifier to continue the transmit path, and
feedback to the RTR6250 IC to complete the frequency control loop. The PA operating band (GSM850
or DCS/PCS) is selected by the MSM device GPIO control (GSM_PA_BAND).

3.3 WCDMA Mode

3.3.1 Receiver

The UMTS duplexer receiver output is routed to LNA circuits within the RFL6202 device. These LNA
functions are removed from the RFR6202 IC to improve mixer LO to RF isolation - a critical parameter
in the Zero-IF architecture. Isolation is further improved using high reverse isolation circuits in the LNA
designs. The LNA gain is controlled by the MSM device to minimize DC power consumption while
achieving the desired RF performance.

The UMTS LNA output is routed to the RFR6202 through a band selection filter that transforms a
single-ended 50Ω source to a differential impedance that is matched to the RFR6202 IC. The RFR input
uses a differential configuration to improve second-order inter-modulation and common mode rejection
performance. The RFR6202 input stages include MSM-controlled gain adjustments that further extend
receiver dynamic range.
The RFR6202 IC (Figure 3.3.1-2) provides the UMTS Zero-IF receiver signal path, from RF to analog
baseband. The input gain stage implements MSM controlled gain adjustments to extend receiver
dynamic range. The amplifier output drives the RF port of the quadrature RF-to-baseband
downconverter then the downconverted baseband outputs are routed to lowpass filters (one I and one
Q) whose passband and stopband characteristics are suitable for DS-WCDMA signals. The filter
outputs are buffered and routed to the MSM device for further processing. This baseband interface is
shared with the RTR6250 GSM850/DCS/PCS receiver outputs.

3. TECHNICAL BRIEF

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Figure 3.3.1-2 RFR6202 IC functional block diagram

Figure 3.3.1-1 RFL6202 IC functional block diagram

3. TECHNICAL BRIEF

- 25 -

The RFR6202 IC includes LO generation and distribution circuitry to reduce offchip component
requirements. The UMTS Rx LO source is created using an external UMTS Rx CH VCO that is closed­loop controlled by the RTR6250 PLL2 via a discrete loop filter. The external UMTS_RX_VCO signal is
processed by the LO generation and distribution circuits to create the quadrature downconverter LO
signal. The LO signal applied at the mixer ports are at a frequency different than the VCO frequency.
This assures that the VCO frequency is different than the RF frequency, an important consideration for
Zero-IF processing. QUALCOMM.s Mobile Station Modem (MSM6275) device provides status and
control signaling, employing power reduction features (such as selective circuit power-down, gain
control, and bias control) to extend handset standby time.

3.3.2 Transmitter

The UMTS transmit path begins with analog baseband signals from the MSM device that drive the
RTR6250 IC. The RTR6250 IC provides all the UMTS transmitter active signal-path circuits except the
power amplifiers. Analog (I and Q) differential signals from the MSM device are buffered, filtered, and
applied to Baseband-to-RF quadrature upconverters. Gain control is implemented on-chip.

The RF outputs include an integrated matching inductor, reducing the off-chip matching network to a
single series capacitor. The RTR6200 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.
The PA device used in CU320 is “Load Insensitive PA”- no need to use isolator - and routed to the
duplexer Tx port directly. Transmit power is delivered from the duplexer to the antenna through the
switch module.

The RTR6250 IC integrates LO generation and distribution circuits on-chip, substantially reducing off­chip requirements. Various modes and programmable features result in a highly flexible transceiver LO
output that supports not only UMTS transmissions, but all GSM850900 and DCS1800/PCS1900 Rx
and Tx modes as well.

The UMTS Tx LO (PLL1) is generated almost entirely on-chip, requiring only the loop filter off-chip
(two capacitors and two resistors); all UMTS Tx VCO and PLL circuits are on-chip. An internal
RTR6250 switch routes the internal VCO signal to the LO generation and distribution circuits to create
the necessary UMTS Tx LO signals.

3. TECHNICAL BRIEF

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3. TECHNICAL BRIEF

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3.4 LO Phase-locked Loop

Most LO functions are fully integrated on-chip, do not require user adjustment, and need not be
considered by handset designers. QUALCOMM has established and implemented frequency plans
and LO generation schemes that support the radioOne 6250-IIseries chipset while requiring minimal
off-chip design effort. Only one area requires handset designer attention: the loop filters of each
phase-locked loop (PLL).

3.4.1 UMTS Rx PLL (PLL2)

UMTS Rx LO functional blocks are distributed between the RFR6202 IC, RTR6250 IC, and external
UMTS_RX_CH_VCO and loop filter components (Figure 3.4.1-1).
The external UMTS_RX_CH_VCO must be enabled for UMTS Rx operation and disabled otherwise; a
dedicated MSM6275 IC signal (UHF_VCO_EN ) enables the VCO.

The RFR6202 IC accommodates single-ended or differential LO inputs; if singleended, either pin can
be active. AC-couple the inactive pin to ground using an appropriately valued capacitor (12 pF is used
in CU320). The 27 pF capacitor should be used to AC-couple the active pin to the VCO signal. Using
only the selected VCO signal, the RFR6202 IC LO generation and distribution circuits create the
necessary LO signals for the active quadrature downconverter.

A sample of the downconverter LO is buffered and routed from RFR6202 IC pin 19 to RTR6250 IC pin
32 (RX_VCO_IN). This signal requires a terminating resistor near the RTR6250 IC input pin and an AC
coupling capacitor that assures the internal RTR6250 IC biasing is not disrupted in the example. Good
microstrip or stripline controlled-impedance techniques must be used

Figure 3.4.1-1 UMTS Rx PLL functional block diagram

Most UMTS Rx PLL circuits are included within the RTR6250 IC: reference divider, phase detector,
charge pump, feedback divider, and digital logic that generate LOCK status. The buffered 19.2 MHz
TCXO signal provides the synthesizer input (REF), the frequency reference to which the PLL is phase
and frequency locked.
The reference is divided by the R-Counter to create a fixed frequency input to the phase detector, FR.
The other phase detector input (FV) varies as the loop acquires lock, and is generated by dividing the
RX_VCO_IN frequency using the feedback path.s N-Counter. The closed loop will force FV to equal
FR when locked. If the loop is not locked the error between FV and FR will create an error signal at the
output of the charge pump. This error signal is filtered by the loop filter and applied to the VCO, tuning
the output frequency such that the error is decreased.
Ultimately the loop forces the error to approach zero and the PLL is phase and frequency locked.

Many key PLL performance characteristics are largely determined by the loop filter design - stability,
transitory response, settling time, and phase noise.

3.4.2 Transceiver PLL (PLL1)

All LO functional blocks for the other handset modes(UMTS Tx, GSM850 Tx/Rx, DCS Tx/Rx, PCS
Tx/Rx) are integrated into the RTR6250 IC except the loop filter components (Figure 3.4.2-1). On-chip
circuits include reference divider, phase detector, charge pump, VCO, feedback divider, and digital
logic status. The functional description given in Section 1.4.1 for the UMTS Rx PLL applies to the
Transceiver PLL as well.

3. TECHNICAL BRIEF

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Figure 3.4.1-2 Transceiver PLL functional block diagram

3. TECHNICAL BRIEF

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The off-chip loop filter allows optimization of key PLL performance characteristics (stability, transitory
response, settling time, and phase noise) for different applications. Guidelines are provided in the next
subsection for proper implementation of this critical circuit.

3.5 Off-chip RF Components

3.5.1 Antenna switch module (U1015 : CXG1198EQ)

The antenna switch module allows multiple operating bands and modes to share the same antenna. In
the CU320 design, a common antenna connects to one of seven paths: 1) UMTS-850 Rx/Tx, 2) 1)
UMTS-1900 Rx/Tx, 3) GSM-850 Rx, 4) GSM-850 Tx, 5)
DCS-1800 Rx, and 6) DCS-1800,PCS-1900 Tx(High Band Tx’s share the same path), 7) 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. GSM band of operation
is time division duplexed, so only the receiver or transmitter is active at any time and a frequency
duplexer is not required. The module includes lowpass filters for the GSM bands transmit paths to
reduce out-of-band emissions, PA harmonics in particular.

3.5.2 UMTS duplexer (FL1013_UMTS1900 : ACMD7402 , FL1012_UMTS850 : B7630 )

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 CU320 typical losses : UMTS1900_ Tx = 2.1 dB, UMTS1900_ Rx = 2.8 dB and UMTS8500_
Tx =1.9 dB, UMTS850_ Rx = 2.7 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 45 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 55 dB.

-. 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.

3.5.3 UMTS Power Amplifier (U1016, U1006)

-. U1016 : WCDMA1900 Power Amplifier module

The WS1413, a Personal Communication Service (PCS) Power Amplifier (PA), is a fully matched 10­pin surface mount module developed for PCS and wireless local loop applications. This power
amplifier module operates in the 1850-1910MHz bandwidth.

The WS1413 meets the stringent spectral linearity requirements of WCDMA transmission with high
power added efficiency for power output of up to 29 dBm. A low current (Vcont) pin is provided for
high efficiency improvement of the low output power range.

The WS1413 is manufactured on an advanced InGaP HBT(Hetero-junction Bipolar Transistor)
MMIC(Microwave Monolithic Integrated Circuit) technology offering state-ofthe-art reliability,
temperature stability and ruggedness.

The 4mmx4mm form factor 10-pin surface mount package is self contained, incorporating 50ohm
input and output matching networks.

-. U1006 : WCDMA850 Power Amplifier module

The WS1102 is a CDMA(Code Division Multiple Access) and AMPS(Advanced Mobile Phone
Service) power amplifier module designed for handsets operating in the 824-849 MHz bandwidth.

The WS1102 meets the stringent spectral linearity requirements of WCDMA transmission with high
power added efficiency for power output of up to 29 dBm. A low current (Vcont) pin provides
improved operating efficiency in the low RF power range

The WS1102is manufactured on an advanced InGaP HBT(Hetero-junction Bipolar Transistor)
MMIC(Microwave Monolithic Integrated Circuit) technology offering state-ofthe-art reliability,
temperature stability and ruggedness.

The 3mmx3mm form factor 8-pin surface mount package is self contained, incorporating 50ohm
input and output matching networks.

3. TECHNICAL BRIEF

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3. TECHNICAL BRIEF

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An isolator between the Power Amplifier and the duplexer is highly recommended to provide constant
load and source impedances (respectively) to those devices. This improves PA stability, ACPR
performance, and harmonic suppression, as well as duplexer isolation, insertion loss, and ripple.
Transmitter performance is always improved when an isolator is included and is well worth the added
cost.

3.5.4 Thermistor (R1040 : 68K_2012_10%)

This thermistor senses temperature variations around UMTS PA to adjust PA gain deviation for assure
compliance with the applicable transmit power control standards. Negative temperature compensation
thermistor is used in the CU320.

Figure 3.5.3-1 UMTS PA functional block diagram