LG U250 User Manual
Date: June, 2007 / Issue 1.0
Service Manual
Model : U250/KU250
Service Manual
U250/KU250
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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 ...........................................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 generation and distribution circuits...25
3.5 Off-chip RF Components .......................25
3.6 Digital Baseband(DBB/MSM6245).........34
3.7 Block Diagram(MSM6245).....................36
3.8 Subsystem(MSM6245) ..........................37
3.9 Power Block...........................................45
3.10 External memory interface...................50
3.11 H/W Sub System..................................52
3.12 Main Features......................................68
4. TROUBLE SHOOTING ...................73
4.1 RF Component.......................................73
4.2 SIGNAL PATH_UMTS RF .....................75
4.3 SIGNAL PATH_GSM RF .......................76
4.4 Checking VC-TCXO Block.....................77
4.5 Checking Front-End Module Block ........79
4.6 Checking UMTS Block...........................81
4.7 Checking GSM Block.............................86
4.8 Checking Bluetooth Block......................92
4.9 Power ON Troubleshooting....................94
4.10 Charger Troubleshooting .....................96
4.11 USB Troubleshooting...........................99
4.12 SIM Detect Troubleshooting ..............100
4.13 Camera Troubleshooting ...................102
4.14 Keypad Backlight Troubleshooting ....105
4.15 Main LCD Troubleshooting ................106
4.16 Receiver Path ....................................107
4.17 Headset path......................................109
4.18 Speaker phone path...........................111
4.19 Main microphone ...............................113
4.20 Headset microphone..........................115
4.21 Vibrator ..............................................117
5. DOWNLOAD..................................119
5.1 U250/KU250 DOWNLOAD ..................119
5.1.1 Introduction ...................................119
5.1.2 Downloading Procedure ...............119
5.1.3 Troubleshooting Download Errors 129
5.1.4 Caution .........................................133
6. BLOCK DIAGRAM ........................134
6.1 GSM & UMTS RF Block.......................134
6.2 Interface Diagram ................................136
7. Circuit Diagram ............................143
8. pcb layout .....................................147
9. Calibration & RF Auto Test
Program (Hot Kimchi)..................149
9.1 Configuration of HOT KIMCHI .............149
9.2 How to use HOT KIMCHI.....................152
10. Factory Test Mode .....................154
10.1. Test Program Setting........................154
10.2. WCDMA Test Mode..........................155
10.3. GSM Test Mode................................156
11. EXPLODED VIEW &
REPLACEMENT PART LIST ..... 157
11.1 EXPLODED VIEW ............................ 157
11.2 Replacement Parts
<Mechanic component>.................... 159
<Main component> ........................... 161
11.3 Accessory ......................................... 174
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
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 WCDMA2100 - Bar type Handset
Size 110.9 X 46.7 X 15.6 mm
Weight Under 83 g (with 950mAh Battery)
Power 3.7 V normal, 950 mAh Li-Ion
Talk Time Over 200 min (WCDMA, Tx=12 dBm, Voice)
(with 950mAh) Over 180 min (GSM, Max Tx Power, Voice)
Standby Time Over 350 Hrs (WCDMA, DRX=1.28)
(with 950mAh) Over 450 Hrs (GSM, Paging period=9)
Antenna Internal type
LCD Main 1.76” TFT, QCIF, 262K
LCD Backlight White LED Back Light
Camera 1.3 Mega pixel + VGA Video Call Camera
Vibrator Yes ( Cylinder Type)
LED Indicator No
MIC Yes
Receiver Yes
Earphone Jack Yes (18 pin)
Connectivity Bluetooth, USB
External Memory Yes(Micro SD)
I/O Connect 18 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 3.7 V(Typ), 3.2 V(Min), [Shut Down : 3.2 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
3 Frequency Error ±0.1ppm ±0.1ppm
4 Phase Error
±5(RMS) ±5(RMS)
±20(PEAK) ±20(PEAK)
3dB below reference sensitivity 3dB below reference sensitivity
Frequency Error RA250 : ±200Hz RA250: ±250Hz
5 Under Multipath and HT100 : ±100Hz HT100: ±250Hz
Interference Condition TU50 : ±100Hz TU50: ±150Hz
TU3 : ±150Hz TU1.5: ±200Hz
0 ~ 100kHz +0.5dB 0 ~ 100kHz +0.5dB
200kHz -30dB 200kHz -30dB
250kHz -33dB 250kHz -33dB
Due to 400kHz -60dB 400kHz -60dB
Output RF
modulation 600 ~ 1800kHz -66dB 600 ~ 1800kHz -60dB
6 1800 ~ 3000kHz -69dB 1800 ~ 6000kHz -65dB
Spectrum
3000 ~ 6000kHz -71dB ≥6000kHz -73dB
≥6000kHz -77dB
Due to
400kHz -19dB 400kHz -22dB
Switching
600kHz -21dB 600kHz -24dB
transient
1200kHz -21dB 1200kHz -24dB
1800kHz -24dB 1800kHz -27dB
2. PERFORMANCE
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No Item GSM DCS & PCS
Frequency offset 800kHz
7 Intermodulation attenuation –
Intermodulation product should
be Less than 55dB below the
level of Wanted signal
Power control
Power Tolerance
Power control
Power Tolerance
Level (dBm) (dB) Level (dBm) (dB)
533±3 030±3
631±3 128±3
729±3 226±3
827±3 324±3
925±3 422±3
10 23 ±3 5 20 ±3
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
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
3)Receiver - GSM Mode
2. PERFORMANCE
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No Item Specification
13 Adjacent Channel Leakage Ratio(ACLR)
33dB@5MHz, ACP>-50dBm
43dB@10MHz, ACP>-50dBm
-36dBm@f=9~150KHz, 1K BW
-36dBm@f=50KHz~30MHz, 10K BW
-36dBm@f=30MHz~1000MHz, 100K BW
14
Spurious Emissions -30dBm@f=1~12.5GHz, 1M BW
(*: additional requirement) (*)-41dBm@f=1893.5~1919.6MHz, 300K
(*)-67dBm@f=925~935MHz, 100K BW
(*)-79dBm@f=935~960MHz, 100K BW
(*)-71dBm@f=1805~1880MHz, 100K BW
15 Transmit Intermodulation
-31dBc@5MHz,Interferer -40dBc
-41dBc@10MHz, Interferer -40dBc
16 Error Vector Magnitude (EVM)
17.5%(>-20dBm)
(@12.2K, 1DPDCH+1DPCCH)
17 Transmit OFF Power
-15dB@SF=4.768Kbps, Multi-code
transmission
No Item GSM DCS & PCS
1
Sensitivity (TCH/FS Class II) -105dBm -105dBm
2
Co-Channel Rejection
C/Ic=7dB Storage -30 ~ +85
(TCH/FS Class II, RBER, TU high/FH)
3 Adjacent Channel 200kHz C/Ia1=-12dB C/Ia1=-12dB
Rejection 400kHz C/Ia2=-44dB C/Ia2=-44dB
Wanted Signal :-98dBm 1st Wanted Signal :-96dBm 1st
4
Intermodulation Rejection interferer:-44dBm 2nd interferer:-44dBm 2nd
interferer:-45dBm interferer:-44dBm
5
Blocking Response Wanted Signal :-101dBm Wanted Signal :-101dBm
(TCH/FS Class II, RBER)
Unwanted : Depend on Frequency Unwanted : Depend on Frequency
2. PERFORMANCE
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4) Receiver - WCDMA Mode
No Item Specification
1 Reference Sensitivity Level -106.7 dBm(3.84 MHz)
-25dBm(3.84MHz)
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)
-44dBm/3.84MHz@f=2050~2095 and
2185~2230MHz
UE@+20dBm output power(Class3)
-30dBm/3.84MHz@f=2025~2050 and
5 Out-band Blocking 2230~2255MHz
UE@+20dBm output power(Class3)
-15dBm/3.84MHz@f=1~2025 and
2255~12500MHz
UE@+20dBm output power(Class3)
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
8 Spurious Emissions -47dBm@f=1~12.5GHz, 1M BW
-60dBm@f=1920MHz~1980MHz, 3.84M BW
-60dBm@f=2110MHz~2170MHz, 3.84M BW
2. PERFORMANCE
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2.4 Current Consumption
1) U250/KU250 Current Consumption
(Stand by and Voice Call Test Condition : Bluetooth off, LCD backlight off,Neighbor Cell off) (VT Test
Condition : Speaker off, LCD backlight On)
2.5 RSSI BAR
Stand by Voice Call VT
WCDMA
Under 2.80 mA Under 290 mA Under 410mA
(DRX=1.28) (Tx=12dBm) (Tx=12dBm)
Under 2.12 mA Under 320 mA
GSM Paging=9 period (Max Tx Power)
Level Change WCDMA GSM
BAR 4 → 3 -85 ± 2 dBm -90 ± 2 dBm
BAR 3 → 2 -95 ± 2 dBm -95 ± 2 dBm
BAR 2 → 1-106 ± 2 dBm -100 ± 2 dBm
BAR 1 → 0-111 ± 2 dBm -106 ± 2 dBm
2.6 Battery BAR
2. PERFORMANCE
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Indication Standby
Bar 4 Over 3.83 ± 0.05V
Bar 4 → 3 3.82 ± 0.05V
Bar 3 → 2 3.73 ± 0.05V
Bar 2 → 1 3.68 ± 0.05V
Bar 1 → Empty 3.58 ± 0.05V
Low Voltage, 3.58± 0.05V (Stand-by) / 3.58 ± 0.05V (Talk)
Warning message+ Blinking [Interval : 3min(Stand-by) / 1min(Talk)]
Power Off 3.20 ± 0.05V
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
• Maximum Charging Current : 700 mA
• Normal Battery Capacity : 950 mAh
• Charging Time : Max 3 hours (except for trickle charging time)
• Full charging indication current (charging icon stop current) : 80 mA
• Cut-off voltage : 3.20 V
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 Idle Noise-Sending (INS) Max -64 dBm0p
6 Idle Noise-Receiving (INR)
Nor Under -47 dBPA
Max Under -36 dBPA
7 Sending Loudness Rating (SLR) 8±3dB
8 Receiving Loudness Rating (RLR)
Nor -1 ±3 dB
Max -12 ±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
TDMA Noise
-. GSM : Power Level : 5
DCS/PCS : Power Level : 0
(Cell Power : -90 ~ -105 dBm)
13
-. Acoustic (Max Vol.)
MS/Headset SLR : 8 ±3dB
MS/Headset RLR : -15 ± 3dB/-12
(SLR/RLR : Mid-value setting)
MS
Headset
MS and
Headset
Max
Under -62 dBm
3. TECHNICAL BRIEF
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3.1 General Description
The U250/KU250 supports UMTS-2100, GSM-900, DCS-1800, and PCS-1900 based
GSM/GPRS/UMTS. All receivers and the UMTS transmitter use the radio One1Zero-IF architecture to
eliminate intermediate frequencies, directly converting signals between RF and baseband. The quadband GSM transmitters use a baseband-to-IF upconversion followed by an offset phase-locked loop
that translates the GMSK-modulated signal to RF.
UMTS (2100)
GSM (900, 1800, 1900)
Bluetooth
1. RTR6275 for GSM Tx
and WCDMA Tx
2. RTR6275 for GSM Rx
and WCDMA Rx
3. Bluetooth RF module
4. PM6650 for power
management
1
QUALCOMM’s branded chipset that implements a Zero-IF radio architecture.
3. TECHNICAL BRIEF
[Fig 1.1] Block diagram of RF part
A generic, high-level functional block diagram of U250/KU250 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).
The UMTS receive path each include a LNA, a RF band-pass filter, and a downconverter that translate
the signal directly from RF-to-baseband using radioOne ZIF technique. The RFIC 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.
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 PA. The high- and low-band UMTS RF transmit signals emerge
from the RTR6275 transceiver.
In the GSM receive paths, 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 transmit paths employ one stage of up-conversion and, in order to improve efficiency.
1. The on-chip quadrature up-converter translates the GMSK-modulated signal to a constant envelope
phase signal at RF;
2. The amplitude-modulated (AM) component is applied to the ramping control pin of power amplifier
from a DAC within the MSM
U250/KU250 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 userdefined off-chip
variables such as temperature, RF output power, and battery ID. Various oscillator, clock, and counter
circuits support IC and higher-level handset functions. Key parameters such as under-voltage lockout
and crystal oscillator signal presence are monitored to protect against detrimental conditions.
3. TECHNICAL BRIEF
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3. TECHNICAL BRIEF
- 19 -
3.2 GSM Mode
3.2.1 GSM Receiver
The Dual-mode U250/KU250’s receiver functions are split among the three RFIC’s as follows:
• GSM-900, DCS-1800, and PCS-1900 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 SBI2-controlled
parameters.
RF Front end consists of antenna, antenna switch module(D5011) which includes three RX saw
filters(GSM900, DCS and PCS). The antenna switch module allows multiple operating bands and
modes to share the same antenna. In U250/KU250, a common antenna connects to one of six paths:
1) UMTS-2100 Rx/Tx, 2) GSM-900 Rx, 3) GSM-900 Tx, 4) DCS-1800 Rx, and 5) DCS-1800 Tx, 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. The GSM900, DCS, and PCS operation is time division
duplexed, so only the receiver or transmitter is active at any time and a frequency duplexer is not
required.
2
The RFIC operating modes and circuit parameters are MSM-controlled through the proprietary 3-line Serial Bus Interface (SBI). The Application
Programming Interface (API) is used to implement SBI commands. The API is documented in AMSS Software - please see applicable AMSS
Software documentation for details.
[Table 1.1] Antenna Switch Module Control logic
GSM 1800 / GSM1900 RX
GSM 900 RX
GSM 900 TX / WCDMA
GSM 1800 / GSM 1900 TX
The GSM900, DCS, and PCS receiver inputs of RTR6275 are connected directly to the transceiver
front-end circuits(filters and antenna switch module). The GSM900, DCS, and PCS 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, 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 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. The RTR input uses a differential configuration to improve second-order intermodulation and common mode rejection performance. The RTR6275 input stages include MSMcontrolled 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 MSM6245 IC for
further processing (an interface shared with the RFR6275 UMTS receiver outputs).
3. TECHNICAL BRIEF
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3. TECHNICAL BRIEF
- 21 -
[Fig 1.2] RTR6275 RX feature
3.2.2 GSM Transmitter
The RTR6275 transmitter outputs(DA_HB2_OUT and DA_LB1_OUT)include on-chip output matching
inductors. The 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 starting value is shown in Figure1.3.
The RTR6275 IC is able to support GSM 900 and GSM 1800/1900 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
3. TECHNICAL BRIEF
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[Fig 1.3] GSM Transmitter matching
6pF
Ω
12pF
Ω
51
39
Ω
9191
Ω
Ω
Ω
100100
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 RFtobaseband 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 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-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 PLL1, the LO generation and distribution circuits create the necessary LO signals for
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
to equal FRF.
The RTR6275 IC is able to support UMTS 2100/1900 and UMTS 850 mode transmitting. This design
guideline shows only UMTS 2100 applications.
3. TECHNICAL BRIEF
- 24 -
[Figure 1.4] RTR6275 IC functional block diagram
WCDMA_2100_TX
WCDMA_2100_RX
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 and UMTS band upconverters
and downconverters; with the help of these LO generation and distribution circuits, 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
2100/1900/1800 transmitter, and all four GSM band receivers and transmitters including: GSM 850,
GSM 900, GSM 1800, and GSM 1900. The second synthesizer (PLL2) provides the LO for the UMTS
2100/1900/1800 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
3.5 Off-chip RF Components
3.5.1 WCDMA PAM (U103: WS2512-TR1G)
The UMTS PA output power is monitored by l power detector circuits(U100 : RTR6275) .
This detector voltage can be used for transmitter calibration and monitor to meet RF system
3. TECHNICAL BRIEF
- 25 -
[Figure 1.5] WCDMA PAM, Duplexer, Coupler
20dB
Rev_1.0
Rev.B
Rev_1.0
Rev.D
WCDMA
7dB
0.5p
L125
FL102
EFCH1950TDF1
2
G13G2
5
G3
1
IN
4
O1
U102
CP0402A1950DNTR
50OHM
4
3
COUP
2IN1
OUT
L404
1.8nH
45
31
NA
L122
KRX102U
TR100
2
1p
C165
3.3p
C162
C159
15p
R122
130
R11951
1.5p
C154
41
RX
TX
2
FL104
ACMD-7602
ANT
3
PGND
130
R121
0.1u
C170
4.7u
C155
47
R120
2
RFOUT
8
1
VCC1VCC2
10
4
VCONT
5
VREF
WS2512_TR1G U103
11
BGND
GND1
3
GND2
6
7
GND3
9
GND4 RFIN
0.5p
C164
100p
C192
C158
15p
1nH
L123
10nH
C157
+VPWR
PA_R0
+VPWR
PWR_DET
PA_ON
VREG_TCXO_2.85V
3.5.2 VCTCXO (X100 : DSA321SCE-19.2M)
The Voltage Controlled Temperature Compensated Crystal Oscillator (VCTCXO) provides the
reference frequency for all RFIC synthesizers as well as clock generation functions within the
MSM6245 IC. The oscillator frequency is controlled by the MSM6245 IC.
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 MSM6245 IC require a reference voltage for proper
operation and sufficient accuracy. Connecting the PM6650 IC REF_OUT directly to the MSM6245 IC
GSM_PA_PWR_CTL_REF provides this reference. This sensitive analog signal needs a 0.1 •ÏF 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.
3.5.3 Front-End Module (U500 : D5011)
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]).
Two GPIO are programmed to be ANT_SEL0_N, ANT_SEL1_N) respectively.
3. TECHNICAL BRIEF
- 26 -
[Table 1.2] Front End Module control logic
GSM 1800 / GSM1900 RX
GSM 900 RX
GSM 900 TX / WCDMA
GSM 1800 / GSM 1900 TX
3. TECHNICAL BRIEF
- 27 -
3.5.4 PMIC Functional Block Diagram (U300 : PM6650-2M)
• 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
• 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)
• 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
3. TECHNICAL BRIEF
- 28 -
[Figure 1.6] MSM6245 Interface
3. TECHNICAL BRIEF
- 29 -
[Figure1.7] PM6650 Block Diagram
3.5.5 GSM PAM (U101 : SKY77318)
The SKY77318 is an extremely small (6 x 6 mm), GSM PAM for handset applications. This module
has been optimized for excellent efficiency and Pout while maintaining high GSM/GPRS efficiency.
The small size and high performance is achieved with high-reliability GaAs HBT technology.
With 50Ω and output, no external matching or bias components are required. The module incorporates
two highly-integrated GaAs power amplifier die with a BiCMOS controller.
Each amplifier has three gain stages with on-die inter-stage matching implemented with a high Q
passives technology for optimal performance. The CMOS controller implements a fully integrated
power control within the module for GSM operations, and serves as the GPRS operations. This
eliminates the need for any external couplers, power detectors, current sensing etc., to assure the
output power level. The module has Tx enable and band select inputs. Module construction is a lowprofile overmolded land-grid array on laminate.
3. TECHNICAL BRIEF
- 30 -
[Figure 1. 8] GSM PAM Schematic
GSM_PA_BAND MODE
8.86dB
HIGH
Rev.D
EGSM
GSM
DCS/PCS
Rev.1.0
LOW
7.5dB
C136
0.01u
10nH
L116
L406 2.7nH
100p
C438
C124
100p
100ohm
R114
NA
5.6p
C441
1.5nH
L403
L115
18nH
100ohm
100ohmR113
R117
100ohm
R107
C153
15p
3
G2
5
G3
1
IN
4
O1
R11091
EFCH897MTDB1
FL101
2
G1
C123
0.01u
39
R112
L111
5.6nH
68p
C139C137
NA
C134
0.01u
GND39GND410GND5
GND612GND713GND814GND9
16
21
P_GND
19
RSVD_GND
VAPC
20
17
VBATT
2
VCC1A
6
VCC1B
BS
1
DCS_PCS_IN
315
DCS_PCS_OUT
EGSM_IN
4
EGSM_OUT
11
ENABLE
18
GND15GND2
7
8
SKY77318
U101
C149
15p
100ohm
R115
91 R111
C121
33u
C138
NA
R108
51
GSM_TX
DCS_PCS_TX
+VPWR
GSM_PA_BAND
GSM_PA_EN
GSM_PA_RA
3. TECHNICAL BRIEF
- 31 -
3.5.6 UMTS Duplexer(FL104:ACMD-7602)
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 U250/KU250 typical
losses : UMTS2100_ Tx = 1.2 dB, UMTS2100_ Rx = 1.4 dB
• Out-of-band rejection or attenuation. the duplexer provides input selectivity for the receiver, output
filtering for the transmitter, and isolation between the two. Rejection levels for both paths are
specified over a number of frequency ranges. Two Tx-to-Rx isolation levels are critical to receiver
performance:
• Rx-band isolation. the transmitter is specified for out-of-band noise falling into the Rx band. This
noise leaks from the transmit path into the receive path, and must be limited to avoid degrading
receiver sensitivity. The required Rx-band isolation depends on the PA out of-band noise levels and
Rx-band losses between the PA and LNA. Minimum duplexer Rx band isolation value is about 51 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 58dB.
• 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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