LG TU500 Service Manual

Date: June, 2006 / Issue 1.0

Service Manual

Model : CU500_TU500

Service Manual

CU500_TU500

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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.............................................19

3.3 UMTS Mode...........................................22

3.4 LO Phase-locked Loop ..........................26

3.5 Off-chip RF Components .......................28

3.6 Digital Baseband(DBB/MSM6275).........35

3.7 Hardware Architecture ...........................36

3.8 Subsystem(MSM6275) ..........................38

3.9 Power Block ...........................................41

3.10 External memory interface ...................46

3.11 H/W Sub System..................................47

3.12 Main Features ......................................64

4. TROUBLE SHOOTING ...................69

4.1 RF Component.......................................69

4.2 SIGNAL PATH_UMTS RF .....................71

4.3 Checking VCXO Block ...........................73

4.4 Checking Ant. SW Module Block ...........75

4.5. Checking UMTS Block ..........................77

4.6. Checking GSM Block ............................84

4.7 Power ON Troubleshooting....................93

4.8 Charger Troubleshooting .......................95

4.9 USB Troubleshooting.............................98

4.10 SIM Detect Troubleshooting ..............100

4.11 Camera Troubleshooting ...................101

4.12 Keypad Backlight Troubleshooting ....102

4.13 Folder ON/OFF Troubleshooting .......103

4.14 Main LCD Troubleshooting ................104

4.15 Audio Receiver Path .........................105

4.16 Headset path......................................107

4.17 Speaker phone path...........................109

4.18 Main microphone ...............................111

4.19 Headset microphone..........................113

5. DOWNLOAD..................................115

5.1 Introduction ..........................................115

5.2 Downloading Procedure.......................115

5.3 Troubleshooting Download Errors .......129

5.4 Caution.................................................134

6. BLOCK DIAGRAM ........................135

6.1 GSM & UMTS RF Block.......................135

6.2 Interface Diagram ................................137

7. Circuit Diagram ............................137

8. pcb layout .....................................148

9. CALIBRATION ..............................153

9.1 HOT KIMCHI........................................153

9.2 How to use Hot Kimchi.........................157

9.3 HOT KIMCHI Example.........................158

10. EXPLODED VIEW &

REPLACEMENT PART LIST ..... 161

10.1 EXPLODED VIEW ............................ 161

10.2 Replacement Parts

<Mechanic component>.................... 163

<Main component> ........................... 166

10.3 Accessory ......................................... 185

Table Of Contents

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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/EGSM/1800/1900 and WCDMA Slim Clamshell

Size 96.5 X 49 X 19.1 mm

Weight 105 g (with Battery)

Power 3.7V normal, 1100 mAh Li-Polymer

Talk Time

Over 180 min (WCDMA, Voice)

Over 180 min (GSM, Voice)

Stand by Time

Over 250 Hrs (WCDMA, DRX=1.28)

Over 250 Hrs (GSM, Paging period=5)

Antenna Intenna Type

LCD TFT Main LCD(2’, 262K, 176 x 220), TFT Sub LCD(65K, 96 x 96)

LCD Backlight White LED Back Light

Camera 1.3 Mega pixel (CMOS)

Vibrator Yes (Cylinder)

LED Indicator No

C-MIC Yes

Receiver Yes

Earphone Jack Yes(2.5mm)

Connectivity Bluetooth, USB

Volume Key Push Type(+, -)

External Memory Micro_SD

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 Class 3 : +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 -104.7 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 3.9 ± 0.05V

Bar 4 → 3 3.9 ± 0.05V

Bar 3 → 2 3.77 ± 0.05V

Bar 2 → 1 3.7 ± 0.05V

Bar 1 → Empty 3.6 ± 0.05V

Low Voltage, 3.50 ± 0.05V (Stand-by) / 3.60 ± 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 4.4 mA Under 366 mA

(DRX=1.28) (Tx=12dBm)

GSM

Under 4.4 mA (Paging=5period) Under 366 mA

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 : 650 mA

• Normal Battery Capacity : 1100 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 CU500 supports UMTS-850, UMTS-1900, GSM-850, GSM-900, DCS-1800, and PCS-1900 based
GSM/GPRS/EDGE/UMTS/HSDPA. 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
phaselocked loop that translates the GMSK-modulated or 8-PSK-modulated signal to RF.

1

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

3. TECHNICAL BRIEF

Fig 3.1 Block diagram of RF part

A generic, high-level functional block diagram of CU500 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 switch module (plus two duplexers for UMTS high-band and low-band operations).

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/GSM900/DCS/PCS receiver outputs.

GSM850, GSM-900, 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/GSM900/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 high-level 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, GSM900, 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/GSM900/DCS/PCS quadrature
upconverter translates the GMSK or 8-PSK-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 off­chip loop filter and dual Tx VCO circuits, and translate the GMSK or 8-PSK-modulated signal to the desired GSM­850, GSM-900, 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.

CU500 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.

3. TECHNICAL BRIEF

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3. TECHNICAL BRIEF

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3.2 GSM Mode

3.2.1 GSM Receiver

The Dual-mode CU500’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, GSM-900, 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(CXG1198AEQ), and three RX saw
filters(GSM850, GSM900, DCS and PCS). The antenna switch module allows multiple operating
bands and modes to share the same antenna. In CU500, a common antenna connects to one of eight
paths: 1) UMTS-850 Rx/Tx, 2) UMTS-1900 Rx/Tx, 3) GSM-850 Rx, 4) GSM-900 Rx, 5) GSM-850
GSM-900 Tx, (Low Band Tx’s share the same path) 6) DCS-1800 Rx, and 7) DCS-1800,PCS-1900
Tx(High Band Tx’s share the same path), 8) 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/GSM900, 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.

IN_A IN_B IN_C

GSM850/GSM900 TX HIGH HIGH LOW

DCS/PCS TX HIGH LOW LOW

GSM 850 RX LOW HIGH LOW

UMTS 850 HIGH LOW HIGH

DCS RX LOW HIGH HIGH

PCS RX LOW LOW HIGH

UMTS 1900 HIGH HIGH HIGH

GSM 900 LOW LOW LOW

Table 3.2.1 Antenna Switch Module Control logic

The GSM850, GSM900, DCS, and PCS receiver inputs of RTR6250 are connected directly to the transceiver
front-end circuits(filters and antenna switch module). GSM850, GSM900, DCS, and PCS receiver inputs are
similar to the RFR6202 UMTS Rx input in that they also use differential configurations to improve commonmode
rejection and second-order non-linearity performance. The balance between the complementary signals is critical
and must be maintained from the RF filter outputs all the way into the IC pins

Since GSM850, GSM900, 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, GSM900, 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 inter­modulation 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 or 8-PSK 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).

3. TECHNICAL BRIEF

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Figure 3.2.1 RTR6250 RX feature

3. TECHNICAL BRIEF

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3.2.2 GSM Transmitter

The shared GSM Low-band (GSM850/GSM900) 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 GMSK or 8-PSK-modulated 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.

Figure 3.2.2-1 Offset phase-locked loop interfaces

The waveform at the dual Tx VCO output is the GMSK or 8-PSK-modulated signal centered at the
desired GSM channel frequency. A phase-locked loop circuit is used to translate the GMSK or 8-PSK­modulated 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/GSM900 or DCS/PCS) is selected by the MSM device GPIO control (GSM_PA_BAND).

3.3 UMTS 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.

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The UMTS LNA output is routed to the RFR6202 through a band selection filter that transforms a
single-ended 50

Ω

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 3.3.1-1) 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/GSM900/DCS/PCS receiver outputs.

Figure 3.3.1-1 RFL6202 IC functional block diagram

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.

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Figure 3.3.1-2 RFR6202 IC functional block diagram

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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 CU500 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 GSM850/900 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.

3.4 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 CU500). 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

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Figure 3.4.1-1 UMTS Rx PLL functional block diagram

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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/GSM900 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 3.4.1 for the UMTS Rx PLL applies to
the Transceiver PLL as well.

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.

Figure 3.4.2-1 Transceiver PLL functional block diagram

3.5 Off-chip RF Components

3.5.1 Antenna switch module (U100 : CXG1198AEQ)

The antenna switch module allows multiple operating bands and modes to share the same antenna. In
the CU500 design, a common antenna connects to one of eight paths: 1) UMTS-850 Rx/Tx, 2) UMTS­1900 Rx/Tx, 3) GSM-850 Rx, 4) GSM-900 Rx, 5) GSM-850/GSM-900 Tx(Low Band Tx’s share the
same path), 6) DCS-1800 Rx, and 7) DCS-1800,PCS-1900 Tx(High Band Tx’s share the same path),

8) 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 (FL106_

UMTS1900 : ACMD7402 , FL107_UMTS850 : B7637 )

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 CU500 typical losses :
UMTS1900_ Tx = 2.1 dB, UMTS1900_ Rx = 2.8 dB and UMTS850_ 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 cross­modulation 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.

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3.5.3 UMTS Power Amplifier (U105 : RF5144)

-. U105 : UMTS 850 Power Amplifier module

The RF5144 is a high-power, high-efficiency linear amplifier module specifically designed for 3V
handheld systems. The device is manufactured on an advanced third generation GaAs HBT process,
and was designed for use as the final RF amplifier in 3V UMTS handheld digital cellular equipment,
spread-spectrum systems, and other applications in the 824MHz to 849MHz band and 1850MHz to
1910MHz band. The RF5144 has a digital control line for low power applications to lower quiescent
current.

3.5.4 Thermistor (R1024 : 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 CU500.

3.5.5 UMTS transmit power detector (U107 : LMV232TLX)

This detector couples PA output power level to calibrate the transmitter characteristic over the channel
variation and temperature. Its detector coupling range and converted voltage is based on diode
sensitivity and transmitter power level.

The CU500 uses National Semiconductor LMV232TLX power detector IC. In Figure 3.5.5-1, RF input
power range of the device has been optimized for use with a 20dB directional coupler, without the
need for additional external componets. The device has two digital interfaces. A Shutdown function is
available to set the device in a low-power shutdown mode. In case SD=High, the device is in
shutdown, if SD=LOW the device is active.The Band-Select function controls the selection of the active
RF input channel. In case BS=HIGH, Rfin1 is active. In case BS=LOW, Rfin2 is active.

Figure 3.5.5-1 Block diagram of LMV232TLX with Coupler

3.5.6 GSM/GPRS/EDGE Power amplifier (U102 : AND0041)

This power amplifier module is designed in a low profile (1.3 mm) and supports dual, tri and quad band
applications for GMSK and 8-PSK modulation schemes using a polar architecture. There aretwo
amplifier chains, one to support GSM850/900 bands, the other for DCS/PCS bands.

The module includes an internal reference voltage and integrated power control scheme for use in
both GMSK and 8-PSK operation. This facilitates fast and easy production calibration and reduces the
number of external components required to complete a power control function. The amplifier's power
control range is typically 55 dB, with the output power set by applying an analog voltage to VRAMP.

All of the RF ports for this device are internally matched to 50Ω . Internal DC blocks are provided at
the RF inputs.

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Figure 3.5.6-1 GSM PA functional block diagram

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3.5.7 GSM transmit VCO (X101 : MQW5V0C869M)

The dual Tx VCO is a key component within the GSM OPLL. This VCO performance directly impacts
PLL and transmitter performance. VCO specifications refer to muRata MQW5V0C869M datasheet.
The dual Tx VCO outputs, one for Low-band GSM and one for high band, drive a resistive network that
splits the active signal into two signals: 1) the input to the active PA . this is the low loss path, and 2)
the OPLL feedback signal . this is the high loss path.
The losses from the VCO outputs to the PA inputs must be factored into the output chain.s power
budget. Each path includes a π-pad that introduces approximately a 3-dB loss. The low band GSM π­pad is formed by R1014 plus R1018, R1021, and R1022; the high band GSM π-pad is formed by
R1016 plus R1019, R1020, and R1022. One leg of each π-pad is used to couple the VCO output to
form the feedback path as described below.
For a given VCO output drive level, the loss to the RTR6250 input must assure the specified input
level is achieved (-18 to -12 dBm). Large resistors included in the π-pads are used to lightly couple off
the VCO outputs to create the feedback signal.
Since the RTR6250 TX_VCO_FB pin presents fairly high impedance, an external terminating resistor
is required (R1022, 51 Ω). A series capacitor (82 pF) AC couples the feedback signal into the
RTR6250 IC.

3.5.8 UMTS Rx RF filter (FL109, FL110)

FL109 - B7837 869 ~ 894MHz GSM850 Rx RF filter
FL110 - B7847 1805 ~1880MHz USPCS1800 Rx RF filter
An RF filter is located between the UMTS LNA and mixer. Insertion loss is important, but not as critical
as losses before the LNA. The most important parameters of this component include:

• Out-of-band rejection or attenuation levels, usually specified to meet these conditions:

- Far out-of-band signals - ranging from DC up to the first band of particular concern and from the
last band of particular concern to beyond three times the highest passband frequency.

- Tx-band leakage - the transmitter channel power, although attenuated by the duplexer, still
presents a cross-modulation threat in combination with Rx-band jammers. The RF filter must
provide rejection of this Tx-band leakage.

- Other frequencies of particular concern . bands known to include other wireless transmitters that
may deliver significant power levels to the receiver input.

• Phase and amplitude balance - the ZIF architecture requires well-balanced differential inputs to the
RFR6202 IC. This is accomplished by the RF filter which takes a single-ended output from the
RFL6202 IC and provides differential outputs having nominal 180°∆ phase separation. Phase and/or
amplitude imbalance causes degraded common-mode rejection and second-order nonlinearity, so
their requirements are specified jointly.

- ±3 degrees and ± 1 dB

- -12 to + 3 degrees and ± 0.7 dB

Of course, passband ripple and return loss are still important in all cases for the same reasons
explained in the antenna switch module and duplexer sections.