LG U8500 User manual

Date: February, 2006 / Issue 1.0
Service Manual Model : U8500
Service Manual
U8500

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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...........................................201
3.2.1 GSM Receiverv................................20
3.2.2 GSM Transmitter..............................22
3.3 WCDMA Mode .......................................23
3.3.1 Receiver...........................................23
3.3.2 Transmitter.......................................25
3.4 Phase-locked Loop ................................26
3.4.1 UMTS Rx PLL (PLL2) ......................26
3.4.2 Transceiver PLL (PLL1)...................27
3.5 Off-chip RF Components .......................28
3.5.1 Front End Module(U1006) ...............28
3.5.2 UMTS duplexer (FL1000) ................29
3.5.3 UMTS Power Amplifier (U1002).......29
3.5.4 Thermistor (RT1000)........................31
3.5.5 UMTS transmit power detector
(U1001)............................................31
3.5.6 Dual band GSM power amplifier
(U1005)............................................32
3.5.7 GSM transmit VCO (U1003) ............34
3.5.8 UMTS Rx RF filter (FL1001) ............34
3.5.9 VCTCXO (X1000) ............................35
3.5.10 Bluetooth........................................35
3. BB Technical Description............. 37
3.6 Baseband(DBB/MSM6250)....................37
3.6.1 General Description .........................37
3.7 Hardware Architecture ...........................38
3.7.1 Block Diagram(MSM6250)...............39
3.8 Subsystem(MSM6250) ..........................40
3.8.1 ARM Microprocessor Subsystem.....40
3.8.2 UMTS Subsystem............................40
3.8.3 GSM Subsystem..............................40
3.8.4 RF Interface .....................................40
3.8.5 Serial Bus Interface(SBI) .................40
3.8.6 Wideband CODEC...........................41
3.8.7 Vocoder Subsystem.........................41
3.8.8 HKADC ............................................41
3.8.9 General-Purpose Input/Output
Interface...........................................41
3.8.10 UART .............................................42
3.8.11 USB ...............................................42
3.9 External memory interface .....................43
3.10 H/W Sub System..................................44
3.10.1 RF Interface ...................................44
3.10.2 MSM Sub System ..........................46
3.10.3 Power Block...................................50
3.10.4 Key Pad .........................................55
3.10.5 Camera Interface ...........................56
3.10.6 Folder ON/OFF Operation .............58
3.10.7 Camera Direction Detection...........59
3.10.8 Keypad Light..................................60
3.10.9 LCD Module...................................61
3.10.10 Display & LCD FPC Interface ......62
3.10.11 Audio and Sound .........................63
3.10.12 Trans Flash..................................67
3.11 Main Features ......................................68
3.11.1 LG-U8500 Main features ...............68
3.11.2 LG-U8500 Main Components ........69
Table Of Contents

Table Of Contents
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4. TROUBLE SHOOTING ...................74
4.1 RF Component.......................................74
4.2 SIGNAL PATH .......................................75
4.3 Checking VCXO Block ...........................76
4.4 Checking Ant. SW Module Block ...........79
4.5 Checking WCDMA Block .......................81
4.5.1 Checking VCXO Block.....................82
4.5.2 Checking Ant. SW module...............82
4.5.3 Checking RF TX Level.....................82
4.5.4 Checking PAM Block .......................84
4.5.5 Check RF Rx Level..........................85
4.6 Checking GSM Block .............................87
4.6.1 Checking VCO Block .......................88
4.6.2 Checking Ant. SW Module...............90
4.6.3 Checking RF Tx level.......................90
4.6.4 Checking PAM Block .......................92
4.6.5 Checking RF Rx Block.....................93
4.7 Bluetooth RF Block ................................95
4.8 Power ON Trouble .................................98
4.9 USB Trouble ........................................100
4.10 SIM Detect Trouble ............................101
4.11 Key Sense Trouble ............................102
4.12 Camera Trouble .................................103
4.13 Main LCD Trouble..............................104
4.14 Keypad Backlight Trouble ..................106
4.15 Folder ON/OFF Trouble .....................107
4.16 Camera Direction Detection Trouble..108
4.17 Trans Flash Trouble...........................109
4.18 Audio Trouble Shooting .....................110
4.19 Charger Trouble Shooting..................120
5. DOWNLOAD .................................123
5.1 Introduction ..........................................123
5.2 Downloading Procedure.......................123
5.3 Troubleshooting Download Errors .......136
6. BLOCK DIAGRAM ........................141
6.1 BLK diagram ........................................141
6.2 GSM & WCDMA RF Block...................142
6.3 Interface Diagram ................................144
7. Circuit Diagram ............................147
8. pcb layout .....................................155
9. CALIBRATION ..............................161
9.1 HOT KIMCHI........................................161
9.1.1 Directory structure..........................161
9.1.2 Setup file (Info_Db.txt) ...................162
9.1.3 Setup file item ................................163
9.1.4 Example for setting file ..................164
9.2 How to use Hot Kimchi.........................165
9.3 HOT KIMCHI Example.........................166
10. EXPLODED VIEW &
REPLACEMENT PART LIST ..... 169
10.1 EXPLODED VIEW ............................ 169
10.2 Replacement Parts
<Mechanic component>.................... 171
<Main component> ........................... 175
10.3 Accessory ......................................... 194

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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 GSM900/1800/1900 and WCDMA Folder Handset
Size 98.8 X 49.0 X 18.2 mm
Weight 93 g (with 800mAh Battery)
Power 4.0V normal, 800 mAh Li-Polymer
Talk Time Over 125 min (WCDMA, Tx=12 dBm, Voice)
(with 800mAh) Over 160 min (GSM, Tx=Max, Voice)
Standby Time Over 200 Hrs (WCDMA, DRX=1.28)
(with 800mAh) Over 220 Hrs (GSM, Paging period=9)
Antenna Internal type
LCD Main 176 X 220 pixel (TFT) / sub 96 X 96 pixel (TFT)
LCD Backlight White LED Back Light (2way ; main/sub common)
Camera 1.3 Mega pixel (CMOS)
Vibrator Yes (Cylinder Type)
LED Indicator No
C-MIC Yes
Receiver Yes
Earphone Jack Yes (12 pin)
Connectivity Bluetooth, USB
Volume Key Push Type(+, -)
External Memory Trans-Flash
I/O Connect 24 Pin

2.2 Usable environment
1) Environment
2) Environment (Accessory)
*CLA : 12 ~ 24 V(DC)
2.3 Radio Performance
1) Transmitter - GSM Mode
* In case of DCS : [A] -> 1710, [B] -> 1785 * In case of PCS : [A] -> 1850, [B] -> 1910
2. PERFORMANCE
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Item Specification
Voltage 4.0 V(Typ), 3.38 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

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
3Frequency Error ±0.1ppm ±0.1ppm
4Phase Error
±5(RMS) ±5(RMS)
±20(PEAK) ±20(PEAK)
3dB below reference sensitivity 3dB below reference sensitivity
Frequency Error RA250 : ±200Hz RA250: ±250Hz
5Under 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
61800 ~ 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
7Intermodulation 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
9Burst timing Mask IN Mask IN

2. PERFORMANCE
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2) Transmitter - WCDMA Mode
No Item Specification
1Maximum Output Power
Class3: +24dBm(+1/-3dB)
Class4: +21dBm(±2dB)
2Frequency Error ±0.1ppm
3Open 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
4Inner 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(10equal command group)
+1 +8/+12 +16/+24
5Minimum 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
7Transmit OFF Power -56dBm(3.84MHz)
8Transmit ON/OFF Time Mask
±25us
PRACH,CPCH,uplinlk compressed mode
±25us
9Change 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
-49 dBc@∆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)
3Adjacent 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
1Reference Sensivitivity Level -106.7dBm(3.84 MHz)
-25dBm(3.84MHz)
2Maximum Input Level -44dBm/3.84MHz(DPCH_Ec)
UE@+20dBm output power(Class3)
3Adjacent 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
5Out-band Blocking 2230~2255MHz
UE@+20dBm output power(Class3)
-15dBm/3.84MHz@f=1~2025 and
2255~12500MHz
UE@+20dBm output power(Class3)
6Spurious Response
-44dBm CW
UE@+20dBm output power(Class3)
-46dBm CW@10MHz
7Intermodulation Characteristic -46dBm/3.84MHz@20MHz
UE@+20dBm output power(Class3)
-57dBm@f=9KHz~1GHz, 100K BW
8Spurious Emissions -47dBm@f=1~12.5GHz, 1M BW
-60dBm@f=1920MHz~1980MHz, 3.84M BW
-60dBm@f=2110MHz~2170MHz, 3.84M BW

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
2. PERFORMANCE
- 14 -
Stand by Voice Call VT
WCDMA
Under 4.0 mA Under 384 mA Under 533mA
(DRX=1.28) (Tx=12dBm) (Tx=12dBm)
Under 3.6 mA Under 300 mA
(Paging=9period) (Tx=Max)
GSM Under 5.3 mA
(@Bluetooth Connected,
Paging=9period)
Level Change WCDMA GSM
BAR 4 →3-87 ±2 dBm -91 ±2 dBm
BAR 3 →2-97 ±2 dBm -96 ±2 dBm
BAR 2 →1-107 ±2 dBm -101 ±2 dBm
BAR 1 →0-111 ±2 dBm -106 ±2 dBm
Indication Standby
Bar 4 Over 3.82 ±0.03V
Bar 4 →33.81 ±0.03V
Bar 3 →23.74 ±0.03V
Bar 2 →13.67 ±0.03V
Bar 1 →Empty 3.50 ±0.03V
Low Voltage, 3.38 ±0.03V (Stand-by) / 3.50 ±0.03V (Talk)
Warning message+ Blinking [Interval : 3min(Stand-by) / 1min(Talk)]
Power Off 3.28 ±0.03V↓

2. PERFORMANCE
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2.7 Sound Pressure Level
No Test Item Specification
1Sending Loudness Rating (SLR) 8 ±3 dB
2Receiving Loudness Rating (RLR) Nor -4 ±3 dB
Max -15 ±3 dB
3Side Tone Masking Rating (STMR) Min 17 dB
4Echo Loss (EL) Min 40 dB
5Sending Distortion (SD) Refer to Table 30.3
6Receiving Distortion (RD) Refer to Table 30.4
7Idle Noise-Sending (INS) Max -64 dBm0p
8Idle Noise-Receiving (INR) Nor Under -47 dBPA
Max Under -36 dBPA
9Sending 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 : -15 ±3dB / -12dB
(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 : 600 mA
• Normal Battery Capacity : 800 mAh
• Charging Time : Max 3.5 hours (except for trickle charging time)
• Full charging indication current (charging icon stop current) : 60 mA
• Cut-off voltage : 3.28 V
2. PERFORMANCE
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3. TECHNICAL BRIEF
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3.1 General Description
The U8500 supports UMTS-2100 DS-WCDMA, EGSM-900, DCS-1800, and PCS-1900. All receivers
and the UMTS transmitter use the radioOne1Zero-IF architecture to eliminate intermediate
frequencies, directly converting signals between RF and baseband. The EGSM, DCS1800 and
PCS1900 transmitters use a baseband-to-IF upconversion followed by an offset phase-locked loop
that translates the GMSK-modulated signal to RF.
1QUALCOMM’s branded chipset that implements a Zero-IF radio architecture.
3. TECHNICAL BRIEF
U8500 high-level RF functional block diagram

A generic, high-level functional block diagram of U8500 is shown in Figure 1-1. One antenna collects
base station forward link signals and radiates handset reverse link signals. The antenna connects with
receive and transmit paths through a switch module (plus a duplexer for UMTS-2100 operation).
UMTS band signals at the antenna are switched to the relevant UMTS duplexer.
The UMTS receive band signals are amplified by the front-end LNAs of the RFR6250 IC before
passing through a band-pass filter and being applied to the mixer inputs of the RFR6250 IC. On-chip
circuits down-convert the received signal directly from RF to baseband using radioOne Zero-IF
techniques. Generation and distribution of the UMTS LO, for the down-converter, is performed entirely
on-chip (except for the loop filter).
The RFR6250 IC outputs analog baseband signals for processing by the MSM device. This baseband
interface is shared with the RTR6250 GSM receiver outputs, but is separate from the GPS baseband
interface.
EGSM, DCS and PCS receive signals from the antenna switch module pass through their band-pass
filters, then are applied to the RTR6250 IC. In a similar fashion to the UMTS paths, RTR6250 IC
circuits down-convert the received signals directly from RF to baseband.
The GSM LO for multiband down conversion is entirely generated within the RTR6250 IC (PLL and
distribution functions) with exception of the off-chip loop filter. The RTR analog baseband outputs are
routed to the MSM6250 IC for further processing (an interface shared with the RFR UMTS receive
paths).
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 EGSM-900, DCS-1800, and PCS-1900 transmit path begins with the same baseband
interface from the MSM6250 IC that is used for the UMTS band. A single EGSM/DCS/PCS quadrature
upconverter translates the GMSK-modulated signal to a convenient intermediate frequency (IF) that
forms one input to an offset phase-locked loop (OPLL).
OPLL functions are split between the RTR6250 IC and off-chip loop filter and dual Tx VCO circuits,
and translate the GMSK-modulated signal to the desired EGSM-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.
3. TECHNICAL BRIEF
- 18 -

3. TECHNICAL BRIEF
- 19 -
U8500 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.

3.2 GSM Mode
3.2.1 GSM Receiver
The Dual-mode U8500’s receiver functions are split between the two RFICs as follows:
• UMTS-2100 operation uses the RFR6250 Receiver ICs to implement the receive signal path,
accepting an RF input and delivering analog baseband outputs (I and Q).
• EGSM-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.
The EGSM, DCS, and PCS receiver inputs of RTR6250 are connected directly to the transceiver front-
end circuits(filters and antenna switch module). EGSM, DCS, and PCS receiver inputs are similar to
the RFR6200 UMTS Rx input in that they also use differential configurations to improve common-
mode rejection and second-order non-linearity performance.
The balance between the complementary signals is critical and must be maintained from the RF filter
outputs all the way into the IC pins.
Since EGSM, 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 EGSM, DCS, and PCS receive signals are routed to the RTR6250 through band selection filters
and matching networks that transform single-ended 50-Ωsources to differential impedances optimized
for gain and noise figure. Similar to the RFR, the RTR input uses a differential configuration to improve
second-order inter-modulation and common mode rejection performance. The RTR6250 input stages
include MSM-controlled gain adjustments that maximize receiver dynamic range.
The amplifier outputs drive the RF ports of the quadrature RF-to-baseband downconverters. The
downconverted baseband outputs are multiplexed and routed to lowpass filters (one I and one Q)
having passband and stopband characteristics suitable for GMSK processing. These filter circuits
include DC offset corrections.
The filter outputs are buffered and passed on to the MSM6250 IC for further processing (an interface
shared with the RFR6200 UMTS receiver outputs).
2The RFIC operating modes and circuit parameters are MSM-controlled through the proprietary 3-line Serial Bus Interface (SBI). The Application
Programming Interface (API) is used to implement SBI commands. The API is documented in AMSS Software - please see applicable AMSS
Software documentation for details.
3. TECHNICAL BRIEF
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3. TECHNICAL BRIEF
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