LG HB620(T), KB620 Service Manual

Service Manual

Model : HB620(T)/KB620

Service Manual

HB620(T)/KB620

Date: June, 2008 / Issue 1.0

Internal Use Only

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

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

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

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

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

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

2.3 Radio Performance ..................................9

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

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

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

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

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

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

3.1 General Description ...............................19

3.2 GSM Mode.............................................21

3.3 UMTS Mode...........................................24

3.4 LO generation and distribution circuits...26

3.5 Off-chip RF Components .......................27

3.6 Digital Baseband (DBB/MSM6280)........43

3.7 Subsystem(MSM6280) ..........................45

3.8 Power Block ...........................................54

3.9 External memory interface .....................59

3.10 H/W Sub System..................................61

3.11 Feature List ..........................................72

4. TROUBLE SHOOTING ...................75

4.1 Power on trouble....................................75

4.2 USB trouble............................................77

4.3 SIM detect trouble..................................78

4.4 Key sense trouble (KEYPAD) ................79

4.5 Keypad backlight trouble........................81

4.6 Micro SD trouble ....................................83

4.7 Audio trouble..........................................84

4.8 Camera trouble ......................................95

4.9 Main LCD trouble ...................................99

4.10 Bluetooth trouble................................102

4.11 RF Component...................................104

4.12 SIGNAL PATH ...................................105

4.13 Checking VCTCXO Block ..................107

4.14 Checking Front-End Module Block ....109

4.15 Checking UMTS Block .......................112

4.16 Checking GSM Block .........................119

4.17 DVB-H/T trouble.................................126

5. DOWNLOAD .................................129

5.1 Introduction ..........................................129

5.2 Downloading Procedure.......................129

5.3 Troubleshooting Download Errors .......142

5.4 Caution.................................................147

6. BLOCK DIAGRAM ........................148

6.1 GSM & UMTS RF Block.......................148

6.2 Interface Diagram ................................150

7. Circuit Diagram ............................153

8. BGM Pin Map................................163

9. PCB LAYOUT................................167

10. CALIBRATION & RF AUTO TEST

(HOT KIMCHI) .............................175

10.1 Usage of Hot-Kimchi ..........................175

11. EXPLODED VIEW &

REPLACEMENT PART LIST ......179

11.1 EXPLODED VIEW .............................179

11.2 Replacement Parts

<Mechanic component>.....................181

<Main component> ............................184

11.3 Accessory ..........................................202

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 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 GSM900/1800/1900 and WCDMA Folder Handset

Size 88.5 x 54.9 x17.9 mm

Weight 110 g (with 1000mAh Battery)

Power 4.0V normal, 1000 mAh(Li-ion) inner-pack

Talk Time Over 180 min (WCDMA, Tx=12 dBm, Voice)

(with 1000mAh) Over 180 min (GSM, Tx=Max, Voice)

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

(with 1000mAh) Over 320 Hrs (GSM, Paging period=5)

Antenna Internal type

LCD Main 320 x 240 pixel (TFT) / sub 34 x 96 pixel (TFT)

LCD Backlight White LED Back Light (2way ; main/sub common)

Camera 2.0 Mega (CMOS) / VGA (CMOS).

Vibrator Yes

LED Indicator No

MIC Yes

Receiver Yes

Earphone Jack Yes (18 pin)

Connectivity Bluetooth, USB

Volume Key Push Type (+, -)

External Memory Trans-Flash

I/O Connect 18 Pin

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2.2 Usable environment

2.2.1 Environment

2.2.2 Environment (Accessory)

* CLA : 12~24V(DC).

2. PERFORMANCE

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Item Specification

Voltage 4.0 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

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2.3 Radio Performance

2.3.1 Transmitter - GSM Mode

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

No Item GSM850/900 DCS & PCS

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

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

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

[B]M~12.75GHz -33dBm

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

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

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

1G~[A]MHz -50dBm 1G~[A]MHz -50dBm

[A]M~[B]MHz -56dBm [A]M~[B]MHz -56dBm

[B]M~12.5GHz -50dBm [B]M~12.5GHz -50dBm

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

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

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

[B]M~4GHz -30dBm

Idle Mode 30M ~ 880MHz -57dBm 30M~880MHz -57dBm

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

915M~1GHz -57dBm 915M~1GHz -57dBm

1G~[A]MHz -47dBm 1G~[A]MHz -47dBm

[A]M~[B]MHz -53dBm [A]M~[B]MHz -53dBm

[B]M~4GHz -47dBm [B]M~4GHz -47dBm

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

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2. PERFORMANCE

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No Item GSM850/900 DCS & PCS

3 Frequency Error ± 0.1ppm ± 0.1ppm

4 Phase Error ± 5(RMS) ± 5(RMS)

± 20(PEAK) ± 20(PEAK)

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

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

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

TU50 : ± 100Hz TU50: ± 150Hz

TU3 : ± 150Hz TU1.5: ± 200Hz

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

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

250kHz -33dB 250kHz -33dB

400kHz -60dB 400kHz -60dB

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

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

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

7 Intermodulation attenuation - Frequency offset 800kHz

Intermodulation product should

be Less than 55dB below the

level of Wanted signal

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No Item GSM850/900 DCS & PCS

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

533 ±3030 ±3

631 ±3128 ±3

729 ±3226 ±3

827 ±3324 ±3

925 ±3422 ±3

10 23 ±3 5 20 ±3

11 21 ±3 6 18 ±3

12 19 ±3 7 16 ±3

13 17 ±3 8 14 ±3

14 15 ±3 9 12 ±4

15 13 ±3 10 10 ±4

16 11 ±5 11 8 ±4

17 9 ±5 12 6 ±4

18 7 ±5 13 4 ±4

19 5 ±5 14 2 ±5

15 0 ±5

9 Burst timing Mask IN Mask IN

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2.3.2 Transmitter - WCDMA Mode

No Item Specification

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

Class 4 : +21dBm( ± 2dB)

2 Frequency Error ± 0.1ppm

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

4 Inner Loop Power control in uplink Adjust output(TPC command)

cmd 1dB 2dB 3dB

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

0 -0.5/+0.5 -0.5/+0.5 -0.5/+0.5

-1 -0.5/-1.5 -1/-3 -1.5/-4.5

Group (10 equel command group)

+1 +8/+12 +16/+24

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

6 Out-of-synchronization handling of output power Qin/Qout : PCCH quality levels

Toff@DPCCH/Ior : -22 -> -28dB

Ton@DPCCH/Ior : -24 -> -18dB

7 Transmit OFF Power -56dBm(3.84MHz)

8 Transmit ON/OFF Time Mask ± 25us

PRACH,CPCH,uplinlk compressed mode

9 Change of TFC ± 25us

Power varies according to the data rate DTX :

DPCH off (minimize interference between UE)

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

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

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

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

10*(∆f-7.5)dBc@∆f=7.5~8.5MHz,1M

-49dBc@∆f=8.5~12.5MHz,1M

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

43dB@10MHz, ACP>-50dBm

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No Item Specification

14 Spurious Emissions (*: additional requirement) -36dBm@f=9~150KHz, 1K BW -

36dBm@f=50KHz~30MHz, 10K BW -

36dBm@f=30MHz~1000MHz, 100K BW

-30dBm@f=1~12.5GHz, 1M BW (*)-

41dBm@f=1893.5~1919.6MHz, 300K

(*)-67dBm@f=925~935MHz, 100K BW

(*)-79dBm@f=935~960MHz, 100K BW

(*)-71dBm@f=1805~1880MHz, 100K BW

15 Transmit Intermodulation -31dBc@5MHz,Interferer -40dBc

-41dBc@10MHz, Interferer -40dBc

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

(@12.2K, 1DPDCH+1DPCCH)

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

-15dB@SF=4.768Kbps, Multi-code

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2. PERFORMANCE

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2.3.3 Receiver - GSM Mode

No Item GSM850/900 DCS & PCS

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

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

Class II, RBER, TU high/FH)

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

Channel

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

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

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

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

5 Blocking Response (TCH/FS Wanted Signal :-101dBm Wanted Signal :-101dBm

Wanted Signal :-101dBm Unwanted : Depend on Unwanted : Depend on

Frequency Frequency

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2. PERFORMANCE

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2.3.4 Receiver - WCDMA Mode

No Item Specification

1 Reference Sensitivity Level -106.7 dBm(3.84 MHz)

2 Maximum Input Level -25dBm(3.84MHz)

-44dBm/3.84MHz(DPCH_Ec)

UE@+20dBm output power(Class3)

3 Adjacent Channel Selectivity (ACS) 33dB

UE@+20dBm output power(Class3)

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

UE@+20dBm output power(Class3)

-44dBm/3.84MHz@15MHz

UE@+20dBm output power(Class3)

5 Out-band Blocking -44dBm/3.84MHz@f=2050~2095 and

2185~2230MHz

UE@+20dBm output power(Class3)

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

2230~2255MHz

UE@+20dBm output power(Class3)

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

2255~12500MHz

UE@+20dBm output power(Class3)

6 Spurious Response -44dBm CW

UE@+20dBm output power(Class3)

7 Intermodulation Characteristic -46dBm CW@10MHz

-46dBm/3.84MHz@20MHz

UE@+20dBm output power(Class3)

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

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

60dBm@f=1850 MHz ≤ f ≤ 1910 MHz,

3.84M BW

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

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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,0dBm Tx power)

2.5 RSSI BAR

2.6 Battery BAR

Stand by(BT Off condition) Voice Call VT

WCDMA Under 3.5 mA Under 320 mA Under 430mA

(DRX=1.28) (Tx=12dBm) (Tx=0dBm)

Under 6.5 mA

(@Bluetooth Connected,

DRX=1.28)

GSM Under 3.5 mA Under 310 mA

(Paging=5period) (Tx=Max)

Under 6.5 mA

(@Bluetooth Connected,

Paging=5period)

No Level Change CDMA GSM

2 BAR 7 → 5 -91 ± 2 dBm -92 ± 2 dBm

3 BAR 5 → 4 -104 ± 2 dBm -97 ± 2 dBm

4 BAR 4 → 2 -108 ± 2 dBm -100 ± 2 dBm

5 BAR 2 → 1 -110 ± 2 dBm -103 ± 2 dBm

6 BAR 1 → 0 -112 ± 2 dBm -105 ± 2 dBm

Indication Standby

Bar 3 Over 3.775 ± 0.1V

Bar 3 → 2 3.775 ± 0.1V

Bar 2 → 1 3.67 ± 0.1V

Bar 1 → Empty 3.56 ± 0.1V

Low Voltage, 3.56 ± 0.1V [Interval: 3min(Stand by)/1min(talk)]

Power Off 3.2 ± 0.1V

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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 1 ± 3 dB

Max -8 ± 3 dB

3 Side Tone Masking Rating (STMR) Min 17 dB

4 Echo Loss (EL) Min 40 dB

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

6 Idle Noise-Receiving (INR) Nor Under -58 dBPA

Max Under -58 dBPA

7 Sending Loudness Rating (SLR) 7 ± 3dB

8 Receiving Loudness Rating (RLR) Nor -6 ± 3 dB

Max -13 ± 3 dB

9 Side Tone Masking Rating (STMR) Min 25 dB

10 Echo Loss (EL) Min 40 dB

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

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

Max Under -40 dBPA

13 TDMA Noise Max Under -62 dBm

-. GSM : Power Level : 5

DCS/PCS : Power Level : 0

(Cell Power : -90 ~ -105 dBm)

-. Acoustic (Max Vol.)

MS/Headset SLR : 8 ± 3 dB

MS/Headset RLR : -15 ± 3 dB/-12 dB

(SLR/RLR : Mid-value setting)

Headset

MS and

Headset

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2. PERFORMANCE

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2.8 Charging

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

• Maximum Charging Voltage : 4.2 V

• Maximum Charging Current : 600 mA

• Normal Battery Capacity : 1000 mAh

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

• Full charging indication current (charging icon stop current) : 193mA

• Cut-off voltage : 3.20 V

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3. TECHNICAL BRIEF

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3.1 General Description

The HB620T supports UMTS-2100, EGSM-900, DCS-1800, and PCS-1900 based GSM/GPRS/EDGE/UMTS. All receivers and the UMTS transmitter use the radioOne1Zero-IF architecture to eliminate intermediate frequencies, directly converting signals between RF and baseband. The quad-band GSM transmitters use a baseband-to-IF upconversion followed by an offset phase-locked loop that translates the GMSK-modulated or 8-PSK-modulated signal to RF.

A generic, high-level functional block diagram of HB620T is shown in [Fig. 3.1]. One antenna collects base station forward link signals and radiates handset reverse link signals. The antenna connects with receive and transmit paths through a FEM(Front End Module).

The UMTS receive paths each include an LNA, an RF band-pass filter, and a downconverter that translate the signal directly from RF-to-baseband using radio One ZIF techniques. The RFIC’s Rx analog baseband outputs, for the receive chains, connect to the MSM IC. The UMTS and GSM Rx baseband outputs share the same inputs to the MSM IC.

[Fig. 3.1] Block diagram of RF part

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

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

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

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

1. The on-chip quadrature upconverter 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

HB620T 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.

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3.2 GSM Mode

3.2.1 GSM Receiver

The Dual-mode HB620T’s receiver functions are operated by only one RFIC as follows:

■ EGSM-900, DCS-1800, PCS-1900 and UMTS-2100 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 (LSHS-M090UH) which includes three RX saw filters (EGSM-900, DCS-1800 and PCS-1900). The antenna switch module allows multiple operating bands and modes to share the same antenna. In HB620T, a common antenna connects to one of six paths: 1) UMTS-2100 Rx/Tx, 2) EGSM-900 Rx, 3) EGSM-900 Tx, 4) DCS-1800 Rx, and 5) DCS-1800, PCS-1900 Tx(High Band Tx’s share the same path), 6) PCS-1900 Rx. UMTS operation requires simultaneous reception and transmission, so the UMTS Rx/Tx connection is routed to a duplexer that separates receive and transmit signals. GSM900, DCS1800, and PCS1900 operation is time division duplexed, so only the receiver or transmitter is active at any time and a frequency duplexer is not required.

The GSM900, DCS1800, and PCS1900 receiver inputs of RTR6275 are connected directly to the transceiver front-end circuits(filters and antenna switch module). GSM900, DCS1800, and PCS1900 receiver inputs use differential configurations to improve common-mode rejection and second-order non-linearity performance. The balance between the complementary signals is critical and must be maintained from the RF filter outputs all the way into the IC pins.

Since GSM900, DCS1800, and PCS1900 signals are time-division duplex (the handset can only receive or transmit at one time), switches are used to separate Rx and Tx signals in place of frequency duplexers - this is accomplished in the switch module.

The 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.

ANT_SEL0 ANT_SEL1 ANT_SEL2

EGSM TX HIGH HIGH LOW

DCS/PCS TX HIGH LOW LOW

UMTS2100 HIGH LOW HIGH

EGSM RX LOW LOW/HIGH LOW

DCS RX LOW HIGH HIGH

[Table 3.1] Antenna Switch Module Control logic

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The GSM900, DCS1800, and PCS1900 receive signals are routed to the RTR6275 through band selection filters and matching networks that transform single-ended 50Ω sources to differential impedances optimized for gain and noise figure. The RTR input uses a differential configuration to improve second-order inter-modulation and common mode rejection performance. The RTR6275 input stages include MSM-controlled gain adjustments that maximize receiver dynamic range.

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

[Fig. 3.2] RTR6275 RX feature

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3.2.2 GSM Transmitter

The RTR6275 transmitter outputs (HB_RF_OUT2 and LB_RF_OUT1) include on-chip output matching inductors. 50ohm output impedance is achieved by adding a series capacitor at the output pins. The capacitor value may be optimized for specific applications and PCB characteristics based on passband symmetry about the band center frequency. The suggested circuit is shown in [Fig. 3.3].

The RTR6275 IC is able to support EGSM900 and DCS1800/PCS1900 mode transmitting. This design guideline shows a tri-band GSM application.

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

[Fig. 3.3] GSM Transmitter matching

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3. TECHNICAL BRIEF

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3.3 UMTS Mode

3.3.1 Receiver

The UMTS duplexer receiver output is routed to LNA circuits within the RTR6275 device. The UMTS Rx input is provided with an on-chip LNA that amplifies the signal before a second stage filter that provides differential downconverter. This second stage input is configured differentially to optimize second-order intermodulation and common mode rejection performance. The gain of the UMTS frontend amplifier and the UMTS second stage differential amplifier are adjustable, under MSM control, to extend the dynamic range of the receivers. The second stage UMTS Rx amplifiers drive the RF ports of the quadrature RFto-baseband downconverters. The downconverted UMTS Rx baseband outputs are routed to lowpass filters having passband and stopband characteristics suitable for UMTS Rx processing. These filter circuits allow DC offset corrections, and their differential outputs are buffered to interface shared with GSM Rx to the MSM IC. The UMTS baseband outputs are turned off when the RTR6275 is downconverting GSM signals and on when the UMTS is operating.

3.3.2 Transmitter

The UMTS Tx path begins with differential baseband signals (I and Q) from the MSM device. These analog input signals are amplified, filtered, and applied to the quadrature upconverter 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-Ω interface.

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

The transceiver LO synthesizer is contained within the RTR6275 IC with the exception of the off-chip loop filter components and the VC-TCXO. This provides a simplified design for multimode applications.

The PLL circuits include a reference divider, phase detector, charge pump, feedback divider, and digital logic generator.

UMTS Tx using only PLL1, the LO generation and distribution circuits create the necessary LO signals for nine different frequency converters. The UMTS transmitter also employs the ZIF architecture to translate the signal directly from baseband to RF. This requires FLO to equal FRF, and the RTR6275 IC design achieves this without allowing FVCO to equal FRF.

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[Fig. 3.4] RTR6275 IC functional block diagram

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3.4 LO generation and distribution circuits

The integrated LO generation and distribution circuits are driven by internal VCOs to support various modes to yield highly flexible quadrature LO outputs that drive all GSM/EDGE and UMTS band upconverters and downconverters; with the help of these LO generation and distribution circuits, true zero-IF architecture is employed in all GSM and UMTS band receivers and transmitters to translate the signal directly from RF to baseband and from baseband to RF.

Two fully functional fractional-N synthesizers, including VCOs and loop filters, are integrated within the RTR6275 IC. The first synthesizer (PLL1) creates the transceiver LOs that support the UMTS 2100 transmitter, and all four GSM band receivers and transmitters including: GSM900, DCS1800, and PCS1900. The second synthesizer (PLL2) provides the LO for the UMTS 2100 receiver. An external TCXO input signal is required to provide the synthesizer frequency reference to which the PLL is phase and frequency locked. The RTR6275 IC integrates most of PLL loop filter components on-chip except two off-chip loop filter series capacitors, and significantly reduces off-chip component requirement. With the integrated fractional-N PLL synthesizers, the RTR6275 has the advantages of more flexible loop bandwidth control, fast lock time, and low-integrated phase error

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3.5 Off-chip RF Components

3.5.1 UMTS PAM (U105: ACPM-7381)

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

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

3.5.2 VCTCXO (X101 : TG-5010LH(19.2M)-75A)

The Voltage Controlled Temperature Compensated Crystal Oscillator (VCTCXO) provides the reference frequency for all RFIC synthesizers as well as clock generation functions within the MSM6280 IC. The oscillator frequency is controlled by the MSM6280 ICs. TRK_LO_ADJ pulse density modulated signal in the same manner as the transmit gain control TX_AGC_ADJ. A two-pole RC lowpass filter is recommended on this control line.

The PM6650 IC controls the handset power-up sequence, including a special VCTCXO warm-up interval before other circuits are turned on. This warm-up interval (as well as other TCXO controller functions) is enabled by the MSM TCXO_EN line. The PM6650 IC VREG_TCXO regulated output voltage is used to power the VCTCXO and is enabled before most other regulated outputs.

Any GSM mode power control circuits within the MSM6280 IC require a reference voltage for proper operation and sufficient accuracy. Connecting the PM6650 IC REF_OUT directly to the MSM6275 IC GSM_PA_PWR_CTL_REF provides this reference. This sensitive analog signal needs a 0.1 µF low frequency filter near to MSM side, and isolate from digital logic and clock traces with ground on both sides, plus ground above and below if routed on internal layers.

[Fig. 3.5] UMTS PAM, Duplexer, Coupler

ANT

ACMD-7602

PGND

FL104

1RX2

+VPWR

C159

LDC151G9520Q-359

33p

SCDY0004101

R120

U104

IN OUT 20dB

TER

COU

R121

120

1nHC162

C166

R119

8 dB

C167 1p

PWR_DET

R122

120

C156

C158

C157

10u

100p

U105ACPM-7381

PGND

110

VCC1

VCC2

GND3

RFIN

RFOUT

VMODE1

VMODE0

GND2

GND1

VEN

C169 100p

C160

10p

C163

C168 100p

DNI

PA_R1

PA_ON

2G23

FL105

EFCH1950TDF1

L125 3.9nH

C164 DNI

WCDMA_2100_TX_OUT

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3.5.3 Front-End Module (FL101 : LSHS-M090UH)

This equipment uses a single antenna to support all handset operating modes, with an antenna switch module select the operating frequency and band. UMTS operation requires simultaneous reception and transmission, so the UMTS Rx/Tx connection is routed to a duplexer that separates receive and transmit signals. The active connection is MSM-selected by three control lines (GPIO[9], GPIO[10], and GPIO[11]). These GPIOs are programmed to be ANT_SEL0, ANT_SEL1, and ANT_SEL2 respectively.

3.5.4 PMIC Functional Block Diagram (U401 : PM6650-3P)

■ Input power management

- Valid external supply attachment and removal detection

- Supports unregulated (closed-loop) external charger supplies and USB supplies as input power sources

- Supports lithium-ion main batteries

- Trickle, constant current, constant voltage, and pulsed charging of the main battery

- Supports coin cell backup battery (including charging)

- Battery voltage detectors with programmable thresholds

- VDD collapse protection

- Charger current regulation and real-time monitoring for over-current protection

- Charger transistor protection by power limit control

- Control drivers for two external pass transistors and one external battery MOSFET - MOSFET is optional

- Voltage, current and power control loops

- Automated recovery from sudden momentary power loss

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ANT_SEL0 ANT_SEL1 ANT_SEL2

EGSM TX HIGH HIGH LOW

DCS/PCS TX HIGH LOW LOW

UMTS2100 HIGH LOW HIGH

EGSM RX LOW LOW/HIGH LOW

DCS RX LOW HIGH HIGH

[Table 3.2] Front End Module control logic

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■ Output voltage regulation

- One boost (step-up) switched-mode power supply (SMPS) for driving white LEDs and hosting USBOTG

- Three buck (step-down) switched-mode power supplies that efficiently generate MSMC, MSME, and PA (or second MSMC) supply voltages

- Supports dynamic voltage scaling (DVS) for MSMC and PA

- Eleven low dropout regulator circuits with programmable output voltages, implemented using three different current ratings: 300 mA (two), 150 mA (six), and 50 mA (three). These can be used to power MSMA, MSMP, RFRX1, RFRX2, RFTX, SYNT, TCXO, WLAN, MMC, USB, and RUIM circuits.

- All regulators can be individually enabled/disabled for power savings

- Low power mode available on MSMA and MSMP regulators

- All regulated outputs are derived from a common bandgap reference - close tracking

■ Integrated handset-level housekeeping functions reduces external parts count, size, cost

- Analog multiplexer selects from 8 internal and up to 18 external inputs

- Multiplexer output’s offset and gain are adjusted, increasing the effective ADC resolution

- Adjusted multiplexer output is buffered and routed to an MSM device ADC

- Dual oscillators - 32.768 kHz off-chip crystal and on-chip RC assures MSM device sleep clock

- Crystal oscillator detector and automated switch-over upon lost oscillation

- Real time clock for tracking time and generating associated alarms

- On-chip adjustments minimize crystal oscillator frequency errors

- Circuits control TCXO warm-up and synchronize, deglitch, and buffer the TCXO signal

- TCXO buffer control for optimal QPH/catnap timing

- Three-stage over-temperature protection (smart thermal control)

■ Integrated handset-level user interfaces

- Four programmable current sinks recommended as keypad backlight, LCD backlight, camera flash, and general-purpose drivers

- Vibration motor driver programmable from 1.2 to 3.1V in 100 mV increments

- Speaker driver with programmable gain, turn-on time, and muting; differential operation (drives

external 8 Ω speakers with volume controlled 500 mW)

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■ IC-level interfaces

- MSM device-compatible 3-line SBI for efficient initialization, status, and control

- Supports the MSM device’s interrupt processing with an internal interrupt manager

- Many functions monitored and reported through real-time and interrupt status signals

- Dedicated circuits for controlled power-on sequencing, including the MSM device’s reset signal

- Several events continuously monitored for triggering power-on/power-off sequences

- Supports and orchestrates soft resets

- USB-OTG transceiver for full-speed (12 Mb/s) and low speed (1.5 Mb/s) interfacing of the MSM

- device to computers as a USB peripheral, or connecting the MSM device to other peripherals

- RUIM level translators enable MSM device interfacing with external modules

■ Twelve multi-purpose pins that can be configured as digital or analog I/Os, bi-directional I/Os, or current sinks. Default functions support the RUIM level translators, power-on circuits, analog multiplexer inputs, an LED driver, and a reference voltage buffer.

■ Highly integrated functionality in a small package - 84-pin BCCS with a large center slug for electrical ground, mechanical stability, and thermal relief.

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[Fig. 3.6] PM6650 Block Diagram

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