LG L705i Service Manual

Date: October, 2008 / Issue 1.0

Service Manual

Model : L705i

Service Manual

L705i

Internal Use Only

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

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

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

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

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

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

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

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

2.5 Antenna BAR .........................................14

2.6 Battery BAR ...........................................15

2.7 Sound Pressure Level............................16

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

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

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

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

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

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

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

3.6 Digital Baseband(DBB/MSM6280).........38

3.7 Block Diagram(MSM6280).....................40

3.8. Subsystem(MSM6280) .........................41

3.9. Power Block..........................................48

3.10. External memory interface..................53

3.11. H/W Sub System.................................54

3.12 Main Features......................................71

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

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

4.2. Checking VCXO Block..........................79

4.3. Checking Ant. SW Module Block ..........81

4.4. Checking UMTS Block..........................83

4.5. Checking GSM Block............................92

4.6. Power ON Troubleshooting...................95

4.7. Charger Troubleshooting ......................98

4.8. USB Troubleshooting..........................101

4.9 SIM Detect Troubleshooting ................103

4.10 1.3 Mega Camera Troubleshooting ...105

4.11 Keypad Backlight Troubleshooting ....107

4.12

FOLDER Close / Open Troubleshooting

..108

4.13 Main LCD Troubleshooting ................109

4.14 Receiver Path ....................................110

4.15 Headset path......................................112

4.16 Speaker phone path...........................114

4.17 Main microphone ...............................116

4.18 Headset microphone..........................118

4.19 Vibrator ..............................................120

5. DOWNLOAD .................................121

5.1 Introduction ..........................................121

5.2 Downloading Procedure.......................121

5.3 Troubleshooting Download Errors .......135

5.4 Caution.................................................141

6. BLOCK DIAGRAM ........................142

6.1 GSM & UMTS RF Block.......................142

6.2 Interface Diagram ................................144

7. Circuit Diagram ............................149

8. BGM Pin Map................................159

9. PCB LAYOUT................................161

10. Calibration & RF Auto Test

Program (Hot Kimchi)................169

10.1 Configuration of HOT KIMCHI ...........169

10.2 How to use HOT KIMCHI...................170

11. EXPLODED VIEW &

REPLACEMENT PART LIST ..... 175

11.1 EXPLODED VIEW ............................ 175

11.2 Replacement Parts

<Mechanic component>.................... 177

<Main component> ........................... 180

11.3 Accessory ......................................... 195

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 commoncarrier telecommunication service of facilities accessed through or connected to it. The manufacturer will not be responsible for any charges that resultfrom such unauthorized use.

B. Incidence of Harm

If a telephone company determines that the equipment provided to customer is faulty and possibly causing harm or interruption in service to the telephone network, it should disconnect telephone service until repair can be done. A telephone company may temporarily disconnect service as long as repair is not done.

C. Changes in Service

A local telephone company may make changes in its communications facilities or procedure. If these changes could reasonably be expected to affect the use of the phones or compatibility with the net work, the telephone company is required to give advanced written notice to the user, allowing the user to take appropriate steps to maintain telephone service.

D. Maintenance Limitations

Maintenance limitations on the phones must be performed only by the manufacturer or its authorized agent. The user may not make any changes and/or repairs expect as specifically noted in this manual. Therefore, note that unauthorized alternations or repair may affect the regulatory status of the system and may void any remaining warranty.

1. INTRODUCTION

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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 Clamshell Folder

Size 100 x 51 x 16.4mm

Weight 99 g (with 860 mAh Battery)

Power 3.7V normal, 860 mAh Li-Polymer

Talk Time

Over 140 Min (WCDMA, Tx=10dBm, Voice Call)

(with 1000mAh)

Over 90 Min (WCDMA, Tx=10dBm, Video Call)

Over 170 Min (GSM, Tx=29dBm, Voice)

Standby Time Over 300 hrs (DRX = 2.56s)

(with 1000mAh) Over 300 hrs (GSM, Paging period = 5)

Antenna Internal Antenna

LCD Main :2.4” QVGA, 262K TFT / Sub : 1.3” 262K TFT

LCD Backlight White

Camera 1.3 Mega pixel (CMOS)

Vibrator Yes (Coin cell type)

LED Indicator Yes ( 2 color LED)

MIC Yes (SMD type)

Receiver Yes (Speaker & Receiver dual mode)

Earphone Jack Yes

Connectivity USB 1.1, IrDA

Volume Key Push Type(+, -)

External Memory No

I/O Connect 10 Pin (ARIB Connector Type A)

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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 3.7 V(Typ), 3.38 V(Min), [Shut Down : 3.28 V]

Operation Temp -20 ~ +60°C

Storage Temp --20 ~ +70°C

Humidity 85 % (Max)

Reference Spec. Min Typ. Max Unit

TA Power Available power 100 220 240 Vac

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

1Spurious 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

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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

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

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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

8Transmitter 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

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2. PERFORMANCE

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2) Transmitter - WCDMA Mode

No Item Specification

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

2Frequency 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

6Out-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

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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

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

-36 dBm @f=150KHz ~ 30MHz, 10k

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

Spurious Emissions -30 dBm @f=1 ~ 12.75GHz, 1M (*: additional requirement) (*)-41 dBm @1893.5 ~ 1919.6MHz, 300k

(*)-67 dBm @925 ~ 935MHz, 100k (*)-79 dBm @935 ~ 960MHz, 100k (*)-71 dBm @1805 ~ 1880MHz, 100k

15 Transmit Intermodulation

-31 dBc @5MHz,Interferer -40dBc

-41 dBc @10MHz,Interferer -40dBc

16 Error Vector Magnitude (EVM)

17.5 % ( >-20dBm) (@12.2k, 1DPDCH+1DPCCH)

17 Transmit OFF Power

-15 dB@SF=4, 768kbps, multi-code transmission

No Item GSM DCS & PCS

Sensitivity (TCH/FS Class II) -102dBm -102dBm

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

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

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

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

(TCH/FS Class II, RBER)

Unwanted: Depend on Frequency Unwanted : Depend on Frequency

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4) Receiver - WCDMA Mode

No Item Specification

1 Reference Sensitivity Level -106.7dBm(3.84M)

-25 dBm(3.84 MHz)

2Maximum 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)

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

2185 ~ 2230 MHz , band a)

UE@ =20dBm output power(class3)

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

5 Out-band Blocking 2230~2255 MHz, band a)

UE@ +20dBm output power(class3)

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

2255 ~ 12500 MHz, band a)

UE@ +20dBm output power(class3)

6Spurious Response

-44dBm CW

UE@ +20dBm output power(class3)

-46 dBm CW@10MHz &

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

UE@ +20dBm output power(class3)

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

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

8 Spurious Emissions

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

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

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2. PERFORMANCE

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2.4 Current Consumption

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

2.5 Antenna BAR

Stand by (Static) Stand by(Dynamic) Voice Call VT

WCDMA

300hrs/300hrs 220hrs/200hrs

140 Min 90 Min

(only mode/auto mode) (only mode/auto mode)

(Tx=10 dBm) (Tx=10 dBm)

(DRX=2.56) (DRX=2.56)

Stand By (Static) - Voice Call

300 hrs/--- hrs

170 Min

GSM (only mode/auto mode) -

(Tx=Max)

(Paging period =5)

Antenna Bar WCDMA GSM

BAR 3

RSCP>= -105 dBm

RSSI >= -95dBm

and Ec/Io >= -12 dBm

BAR 2

-110 <= RSCP < -105 dBm

-100 <= RSSI < -95 dBm

or -14 <= Ec/Io < -12 dBm

BAR 1

-113 <= RSCP < -110 dBm

-105 <= RSSI < -100 dBm

or -17 <= Ec/Io < -14 dBm

BAR 0

RSCP < -113 dBm

-110 <= RSSI < -105 dBm

or Ec/Io < -17 dBm

Network Notification Network Notification

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2.6 Battery BAR

2. PERFORMANCE

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Indication Voltage

During Idle state During Call state

BAR 3 -> 2

3.78 ± 0.05V 3.67 ± 0.05V

(call maintenance over 40min)

BAR 2 -> 1

3.67 ± 0.05V 3.57 ± 0.05V

(call maintenance over 10min)

BAR 1 -> 0

3.3V ± 0.05V 3.28V ± 0.05V

(Icon Blinking)

Low battery message BAR 1 -> 0

Low battery pop-up BAR 2 -> 1, display one time

Power OFF during call - 80s after Low battery message

Power OFF at stand-by 60s after Low battery message -

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2. PERFORMANCE

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2.7 Sound Pressure Level

2.8 Charging

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

• Maximum Charging Voltage: 4.2 V

• Normal Charging Current: 600 mA

• Normal Battery Capacity: 860 mAh

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

• Full charging indication current (charging icon stop current): 140 mA

• Cut-off voltage:

Stand-by: 3.30 V, Talk: 3.28 V low temperature (under -10deg.): 3.00V

No Test Item Specification

1 Sending Loudness Rating (SLR) 8 ±3 dB

2 Receiving Loudness Rating (RLR)

Nor -4 ± 3 dB

Max -15 ± 3 dB 3 Side Tone Masking Rating (STMR) Min 17 dB 4 Echo Loss (EL) Min 40 dB 5 Sending Distortion (SD) Refer to Table 30.3 6 Receiving Distortion (RD) Refer to Table 30.4 7 Idle Noise-Sending (INS) Max -64 dBm0p

8 Idle Noise-Receiving (INR)

Nor Under -47 dBPA

Max Under -36 dBPA 9 Sending Loudness Rating (SLR) 8 ± 3 dB

10 Receiving Loudness Rating (RLR)

Nor -1 ± 3 dB

Max -12 ± 3 dB

11 Side Tone Masking Rating (STMR) Min 25 dB 12 Echo Loss (EL) Min 40 dB 13 Sending Distortion (SD) Refer to Table 30.3 14 Receiving Distortion (RD) Refer to Table 30.4 15 Idle Noise-Sending (INS) Max -55 dBm0p

16 Idle Noise-Receiving (INR)

Nor Under -45 dBPA

Max Under -40 dBPA

TDMA Noise

-. GSM: Power Level: 5 DCS/PCS: Power Level: 0 (Cell Power: -90 ~ -105 dBm)

-. Acoustic (Max Vol.) MS/Headset SLR: 8 ±3dB MS/Headset RLR: -15 ± 3dB/-12 (SLR/RLR : Mid-value setting)

Headset

MS and

Headset

Max

-62 dBm

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3. TECHNICAL BRIEF

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3.1 General Description

The L705i supports UMTS-800, UMTS-2100, GSM-900, DCS-1800, and PCS-1900 based GSM/GPRS/UMTS. All receivers and the UMTS transmitter use the radioOne1Zero-IF architecture to eliminate intermediate frequencies, directly converting signals between RF and baseband. The triband GSM transmitters use a baseband-to-IF upconversion followed by an offset phase-locked loop that translates the GMSK-modulated or 8-PSK-modulated signal to RF.

A generic, high-level functional block diagram of L705i 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 FEM(Front End Module) (plus two duplexers for UMTS high-band and lowband operations).

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

3. TECHNICAL BRIEF

Fig 3.1 Block diagram of RF part

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The UMTS receive paths each include an LNA, an RF band-pass filter, and a downconverter that translate the signal directly from RF-to-baseband using radioOne ZIF techniques. The high-band UMTS receive path and low-band path are accommodated in the RTR6275 IC. The RFIC.s Rx analog baseband outputs, for the receive chains, connect to the MSM IC. The UMTS and GSM Rx baseband outputs share the same inputs to the MSM IC (at ADC1).

For the transmit chains, the RTR6275 IC directly translates the Tx baseband signals (from the MSM device) to an RF signal using an internal LO generated by integrated on-chip PLL and VCO. The RTR6275 IC outputs deliver fairly high-level RF signals that are first filtered by Tx SAWs and then amplified by their respective UMTS PAs. The high- and low-band UMTS RF transmit signals emerge from the RTR6275 transceiver.

In the GSM receive path, the received RF signals are applied through their band-pass filters and down-converted directly to baseband in the RTR6275 transceiver IC. These baseband outputs are shared with the UMTS receiver and routed to the MSM IC for further signal processing. The RFR6275 GSM/UMTS IC receiver baseband outputs share the same interface to the MSM IC input ADC as the RTR6275 IC baseband outputs.

The GSM transmit path employs one stage of up-conversion and, in order to improve efficiency, is divided into phase and amplitude components to produce an open-loop Polar topology:

1. The on-chip quadrature up-converter translates the GMSK-modulated signal or 8-PSK modulated signal, to a constant envelope phase signal at RF

2. The amplitude-modulated (AM) component is applied to the ramping control pin of Polar power amplifier from a DAC within the MSM

L705i 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 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. 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

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 L705i’s receiver functions are split between the three RFICs as follows:

• UMTS-800 operation uses the RFR6275 Receiver ICs to implement the receive signal path, accepting an RF input and delivering analog baseband outputs (I and Q).

• UMTS-2100, GSM-900, DCS-1800, and PCS-1900 modes use the RTR6275 IC only. Each mode has independent front-end circuits and down-converters, but they share common baseband circuits (with only one mode active at a time). All receiver control functions are beginning with SBI2controlled parameters.

RF Front end consists of antenna, antenna switch module(D2024) which includes four RX saw filters(GSM850, GSM900, DCS and PCS). The antenna switch module allows multiple operating bands and modes to share the same antenna. In L705i, a common antenna connects to one of eight paths: 1) UMTS-800 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.

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.

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The GSM900, DCS, and PCS receiver inputs of RTR6275 are connected directly to the transceiver frontend circuits(filters and antenna switch module). GSM900, DCS, and PCS receiver inputs are similar to the RFR6275 UMTS Rx input in that they also use differential configurations to improve common-mode rejection

Since 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 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

signals in place of frequency duplexers - this is accomplished in the switch module.

The GSM900, DCS, and PCS receive signals are routed to the RTR6275 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 RTR6275 input stages include MSM-controlled gain adjustments that maximize receiver dynamic range.

The amplifier outputs drive the RF ports of the quadrature RF-to-baseband downconverters. The downconverted baseband outputs are multiplexed and routed to lowpass filters (one I and one Q) having passband and stopband characteristics suitable for GMSK or 8-PSK processing. These filter circuits include DC offset corrections. The filter outputs are buffered and passed on to the MSM6280 IC for further processing (an interface shared with the RFR6275 UMTS receiver outputs

3. TECHNICAL BRIEF

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Switch Mode CTRL1 CTRL2 CTRL3

GSM850/EGSM TX 1 0 1

PCN/PCS TX 0 1 1

WB850 0 1 1

WB1900 0 0 1

WB2100 1 0 1

GSM850 RX 0 0 0

EGSM RX 1 0 0

PCN RX 1 1 0

PCS RX 0 1 0

All Off 1 1 1

ANENNA SWITCH MODULE LOGIC

Table 3.2.1 Antenna Switch Module Control logic

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Fig 3.2.1 RTR6275 RX feature

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3.2.2 GSM Transmitter out put

The RTR6275 transmitter outputs(DA_HB2_OUT and DA_LB1_OUT)include on-chip output matching inductors. 50ohm output impedance is achieved by adding a series capacitor at the output pins. The capacitor value may be optimized for specific applictions and PCB characteristics based on pass-band symmetry about the band center frequency, the suggested starting value is shown in Figure1.2.

The RTR6275 IC is able to support GSM 850/1900 and GSM 1800/1900 mode transmitting. This design guideline shows a quad-band GSM application.

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

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Figure 3.2.2 GMS Transmitter matching

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3.3 UMTS Mode

3.3.1 Receiver

The UMTS duplexer receiver outputs are routed to LNA circuits within the RFR6275 and RTR6275 device.

UMTS LNA circuits(one for low-band UMTS and one for high-band UMTS path) are separated from all other receive functions contained within the RFR6275 and RTR6275 reveiver ICs to improve mixer LO to RF isolation- a critical parameter in the ZIF architecture. Isolation is further improved using highreverse isolation circuits in the LNA designs.

The LNA gains are stepped via API control. The IC operating mode and LNA bias currents are automatically adjusted via software to minimize DC power consumption.

Figure 3.3.1 RFR6275 IC functional block diagram

WCDMA_800_RX

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The inputs use differential configurations to improve second-order intermodulation and common-mode rejection performance. The differential input gain stage implements MSM IC-controlled gain adjustments to extend receiver dynamic range.

The outputs of the differential amplifiers drive the RF port of the quadrature RF-to-baseband downconverters. The down-converters are routed to low-pass filters (one I and one Q) whose pass-band and stop-band characteristics supplement MSM device processing. These filter circuits allow for DC offset correction and the differential I/Q outputs are buffered to interface with the MSM IC.

Numerous secondary functions also are integrated on-chip: the Rx LO generation and distribution circuits and various interface, control, and status circuits. An on-chip UMTS VCO is phase locked to the external VC-TCXO signal and processed, by the LO generation and distribution circuits, to create the UMTS Rx LO signals for the quadrature down-converter. The LO signal, applied to its mixer, is at frequencies different to that of the VCO, which is an important consideration for ZIF processing. The QUALCOMM MSM 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 3.3.2 RTR6275 IC functional block diagram

WCDMA_2100_RX

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3.3.1 Transmitter

The UMTS Tx path begins with differential baseband signals (I and Q) from the MSM device. These analog input signals are amplified, filtered, and applied to the quadrature up-converter mixers. The upconverter output is amplified by multiple variable gain stages that provide transmit AGC control. The AGC output is filtered and applied to the driver amplifier; this output stage includes an integrated matching inductor that simplifies the external matching network to a single series capacitor to achieve the desired 50-ßŸ interface.

The RTR6275 UMTS output is routed to its power amplifier through a bandpass filter, and delivers fairly high-level signals that are filtered and applied to the PA. Transmit power is delivered from the duplexer to the antenna through the switch module.

The transceiver LO synthesizer is contained within the RTR6275 IC with the exception of the off-chip loop filter components and the VC-TCXO. This provides a simplified design for multimode applications. The PLL circuits include a reference divider, phase detector, charge pump, feedback divider, and digital logic generator.

UMTS Tx. Using only PLL1, the LO generation and distribution circuits create the necessary LO signals for nine different frequency converters.

the UMTS transmitter also employs the ZIF architecture to translate the signal directly from baseband to RF. This requires FLOto equal FRF, and the RTR6275 IC design achieves this without allowing F

VCO

equal FRF.

The RTR6275 IC is able to support UMTS 2100/1900 and UMTS 800 mode transmitting. This design guideline shows only UMTS 2100/1900 and UMTS 800 applications.

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Figure 3.3.3 RTR6275 IC functional block diagram

WCDMA_2100_TX

WCDMA_800_TX

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3.4 LO Phase-locked Loop

All LO functions are fully integrated on-chip and do not require user any adjustment. QUALCOMM has established and implemented frequency plans and LO generation schemes that support the radioOne Platform B-series chipset. Only one area requires handset designer attention: the loop filters relating to each PLL. These are addressed in this chapter. All the UMTS Rx, GSM Rx, and GPS PLL circuits are included within the RFICs: reference dividers, phase detectors, charge pumps, feedback dividers, and digital logic. There are four integrated VCOs and PLLs within the Platform B (RFCMOS) chipset as shown in Figure

3.4.1 and Figure 3.4.2

■ Figure 3.4-1

1. PLL1, within the RTR6275 IC, produces the LO for up- and down-conversion of GSM Tx/Rx, and

UMTS Tx.

2. PLL2, within RTR6275 IC, produces the Rx LO for one of the (high band) UMTS receive Paths.

■ Figure 3.4.2

3. PLL3, within the RFR6275 IC, produces the Rx LO for the remaining UMTS receive paths.

4. PLL4, within the RFR6275 IC, produces the Rx LO for the GPS receive path.

Within the RFICs, a 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-Counters 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 VCO frequency using the feedback path 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 components and applied to the VCO, tuning the output frequency so that the error is decreased. Ultimately, the loop forces the error to approach zero and the PLL is phase- and frequency-locked.

Figure 3.4.1 / Figure 3.4.2 RFR6275 PLL’s functional block diagram

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3.4.1 UMTS Rx PLL (PLL2)

QUALCOMM provides a baseline PLL3 design for UMTS Rx. Loop filter component reference designators are shown in Figure 3.4.2.

Notes: 1. The performance values listed in this table are based on simulation results and are provided

as a starting point for handset designers. Synthesizer performance is still being evaluated and optimized during this document release. Loop parameter, settling time, and filter component values are all expected to change when the optimization effort is completed. Future revisions will include expected performance based on measured data.

2. For L705i, C1_2.2nF C2_150pF R1_10k

3. Loop parameter acronyms are: Kvco VCO tuning sensitivity CP_I Charge pump current (controlled by API software) PM Phase margin L_BW Loop bandwidth

4. The listed VCO tuning sensitivity is based on QUALCOMM internal Rx VCO.

5. The listed settling times are for switching between channels at opposite ends of the active band and settling to within 250 Hz of the final frequency.

6. Test and evaluation efforts were ongoing at the time of this document release. Check future versions for design recommendations based on our test results.

3.4.2 Transceiver PLL (PLL1)

The PLL1 within the RTR6275 IC creates the Rx LO for all the GSM receive bands and GSM transmit bands as well as the UMTS transmit bands. The PLL1 of RTR6275 IC (with on-chip VCO) creates the transceiver LO that supports the quad-band GSM receivers and the GSM transmitters as well as the tri-band UMTS transmit outputs. All LO functional blocks are integrated into the RTR6275 IC except for some loop filter capacitors (Figure 3.4.1). On-chip circuits include reference divider, phase detector, charge pump, VCO, feedback divider, and digital logic status. The off-chip loop filter capacitors allow minimal optimization of PLL performance characteristics (stability, transitory response, settling time, and phase noise) for different applications.

Table 3.4.1 Baseline PLL2 design for UMTS Rx

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3.5 Off-chip RF Components

3.5.1 Antenna switch module (FL100: DGM099M01)

Switch Mode CTRL1 CTRL2 CTRL3

GSM850/EGSM TX 1 0 1

PCN/PCS TX 0 1 1

WB850 0 1 1

WB1900 1 0 1

WB2100 0 0 1

GSM850 RX 0 0 0

EGSM RX 1 0 0

PCN RX 1 1 0

PCS RX 0 1 0

All Off 1 1 1

Table 3.5.1 FEM control table

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3.5.2 UMTS duplexer

(FL103: SAYZY1G95EA0B00, FL106: EFSD836MF2S2 ) 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 L705i typical losses: UMTS2100_ Tx = 1.6dB, UMTS2100_ Rx = 2.1dB and UMTS800_ Tx =1.0dB, UMTS800_ Rx = 1.5dB

■ 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.

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3.5.3 UMTS Power Amplifier

(U104: AWT6277R / U106: AWT6307R) U104: UMTS2100 / U106: UMTS800 Power Amplifier modules

* AWT6277R Description: The AWT6277 meets the increasing demands for higher output power in UMTS handsets. The PA module is optimized for Vref = +2.85V, a requirement for compatibility with the Qualcomm 6250 chipset. The device is manufactured on an advanced InGaP HBT MMIC technology offering state-of-the-art reliability, and ruggedness. Selectable bias modes that optimize efficiency for different output power levels, and a shutdown mode with low leakage current, increase handset talk and standby time.

The self-contained 4mm*4mm*1.1mm surface mount package incorporates matching networks optimized for output power, efficiency, and linearity in a 50Ω system.

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Figure 3.5.1 AWT6277R Functional block

diagram

Figure 3.5.2 AWT6277R Pin description

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