LG L705i User manual

Date: October, 2008 / Issue 1.0
Service Manual Model : L705i
Service Manual
L705i
Internal Use Only
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1. INTRODUCTION .............................. 5
1.1 Purpose................................................... 5
1.2 Regulatory Information............................ 5
2. PERFORMANCE...............................7
2.1 System Overview.....................................7
2.2 Usable environment.................................8
2.3 Radio Performance..................................8
2.4 Current Consumption.............................14
2.5 Antenna BAR .........................................14
2.6 Battery BAR ...........................................15
2.7 Sound Pressure Level............................16
2.8 Charging ................................................16
3. TECHNICAL BRIEF ........................17
3.1 General Description ...............................17
3.2 GSM Mode.............................................19
3.3 UMTS Mode...........................................23
3.4 LO Phase-locked Loop ..........................27
3.5 Off-chip RF Components .......................29
3.6 Digital Baseband(DBB/MSM6280).........38
3.7 Block Diagram(MSM6280).....................40
3.8. Subsystem(MSM6280) .........................41
3.9. Power Block..........................................48
3.10. External memory interface..................53
3.11. H/W Sub System.................................54
3.12 Main Features......................................71
4. TROUBLE SHOOTING ...................77
4.1 RF Component.......................................77
4.2. Checking VCXO Block..........................79
4.3. Checking Ant. SW Module Block ..........81
4.4. Checking UMTS Block..........................83
4.5. Checking GSM Block............................92
4.6. Power ON Troubleshooting...................95
4.7. Charger Troubleshooting ......................98
4.8. USB Troubleshooting..........................101
4.9 SIM Detect Troubleshooting ................103
4.10 1.3 Mega Camera Troubleshooting ...105
4.11 Keypad Backlight Troubleshooting ....107
4.12 FOLDER Close / Open Troubleshooting
..108
4.13 Main LCD Troubleshooting ................109
4.14 Receiver Path ....................................110
4.15 Headset path......................................112
4.16 Speaker phone path...........................114
4.17 Main microphone ...............................116
4.18 Headset microphone..........................118
4.19 Vibrator ..............................................120
5. DOWNLOAD .................................121
5.1 Introduction ..........................................121
5.2 Downloading Procedure.......................121
5.3 Troubleshooting Download Errors .......135
5.4 Caution.................................................141
6. BLOCK DIAGRAM ........................142
6.1 GSM & UMTS RF Block.......................142
6.2 Interface Diagram ................................144
7. Circuit Diagram ............................149
8. BGM Pin Map................................159
9. PCB LAYOUT................................161
10. Calibration & RF Auto Test
Program (Hot Kimchi)................169
10.1 Configuration of HOT KIMCHI ...........169
10.2 How to use HOT KIMCHI...................170
11. EXPLODED VIEW &
REPLACEMENT PART LIST ..... 175
11.1 EXPLODED VIEW ............................ 175
11.2 Replacement Parts
<Mechanic component>.................... 177
<Main component> ........................... 180
11.3 Accessory ......................................... 195
Table Of Contents
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LGE Internal Use Only Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
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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
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E. Notice of Radiated Emissions
This model complies with rules regarding radiation and radio frequency emission as defined by local
regulatory agencies. In accordance with these agencies, you may be required to provide information
such as the following to the end user.
F. Pictures
The pictures in this manual are for illustrative purposes only; your actual hardware may look slightly
different.
G. Interference and Attenuation
A phone may interfere with sensitive laboratory equipment, medical equipment, etc. Interference from
unsuppressed engines or electric motors may cause problems.
H. Electrostatic Sensitive Devices
ATTENTION
Boards, which contain Electrostatic Sensitive Device (ESD), are indicated by the sign.
Following information is ESD handling:
• Service personnel should ground themselves by using a wrist strap when exchange system boards.
• When repairs are made to a system board, they should spread the floor with anti-static mat which is
also grounded.
• Use a suitable, grounded soldering iron.
• Keep sensitive parts in these protective packages until these are used.
• When returning system boards or parts like EEPROM to the factory, use the protective package as
described.
1. INTRODUCTION
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2. PERFORMANCE
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2.1 System Overview
2. PERFORMANCE
Item Specification
Shape Clamshell Folder
Size 100 x 51 x 16.4mm
Weight 99 g (with 860 mAh Battery)
Power 3.7V normal, 860 mAh Li-Polymer
Talk Time Over 140 Min (WCDMA, Tx=10dBm, Voice Call)
(with 1000mAh) Over 90 Min (WCDMA, Tx=10dBm, Video Call)
Over 170 Min (GSM, Tx=29dBm, Voice)
Standby Time Over 300 hrs (DRX = 2.56s)
(with 1000mAh) Over 300 hrs (GSM, Paging period = 5)
Antenna Internal Antenna
LCD Main :2.4” QVGA, 262K TFT / Sub : 1.3” 262K TFT
LCD Backlight White
Camera 1.3 Mega pixel (CMOS)
Vibrator Yes (Coin cell type)
LED Indicator Yes ( 2 color LED)
MIC Yes (SMD type)
Receiver Yes (Speaker & Receiver dual mode)
Earphone Jack Yes
Connectivity USB 1.1, IrDA
Volume Key Push Type(+, -)
External Memory No
I/O Connect 10 Pin (ARIB Connector Type A)
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2.2 Usable environment
1) Environment
2) Environment (Accessory)
* CLA: 12 ~ 24 V(DC)
2.3 Radio Performance
1) Transmitter-GSM Mode
* In case of DCS: [A] -> 1710, [B] -> 1785 * In case of PCS: [A] -> 1850, [B] -> 1910
2. PERFORMANCE
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Item Specification
Voltage 3.7 V(Typ), 3.38 V(Min), [Shut Down : 3.28 V]
Operation Temp -20 ~ +60°C
Storage Temp --20 ~ +70°C
Humidity 85 % (Max)
Reference Spec. Min Typ. Max Unit
TA Power Available power 100 220 240 Vac
No Item GSM DCS & PCS
100k ~ 1GHz -39dBm 9k ~ 1GHz -39dBm
MS allocated 1G ~ [A]MHz -33dBm
Channel 1G ~ 12.75GHz -33dBm [A]M ~ [B]MHz -39dBm
Conducted [B]M ~ 12.75GHz -33dBm
1Spurious 100k ~ 880MHz -60dBm 100k ~ 880MHz -60dBm
Emission 880M ~ 915MHz -62dBm 880M ~ 915MHz -62dBm
Idle Mode 915M ~ 1GHz -60dBm 915M ~ 1GHz -60dBm
1G ~ [A]MHz -50dBm 1G ~ [A]MHz -50dBm
[A]M ~ [B]MHz -56dBm [A]M ~ [B]MHz -56dBm
[B]M ~ 12.5GHz -50dBm [B]M ~ 12.5GHz -50dBm
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2. PERFORMANCE
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* In case of DCS : [A] -> 1710, [B] -> 1785 * In case of PCS : [A] -> 1850, [B] -> 1910
No Item GSM DCS & PCS
30M ~ 1GHz -36dBm 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
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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
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2. PERFORMANCE
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2) Transmitter - WCDMA Mode
No Item Specification
1Maximum Output Power Class 3: +24dBm(+1/-3dB)
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 (10 equel 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
-49dBc@∆f=8.5 ~ 12.5MHz,1M
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3)Receiver - GSM Mode
2. PERFORMANCE
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No Item Specification
13 Adjacent Channel Leakage Ratio(ACLR) 33dB@5MHz, ACP>-50dBm
43dB@10MHz, ACP>-50dBm
-36 dBm @f=9 ~ 150KHz, 1k BW
-36 dBm @f=150KHz ~ 30MHz, 10k
-36 dBm @f=30 ~ 1000MHz, 100k
14 Spurious Emissions -30 dBm @f=1 ~ 12.75GHz, 1M
(*: additional requirement) (*)-41 dBm @1893.5 ~ 1919.6MHz, 300k
(*)-67 dBm @925 ~ 935MHz, 100k
(*)-79 dBm @935 ~ 960MHz, 100k
(*)-71 dBm @1805 ~ 1880MHz, 100k
15 Transmit Intermodulation -31 dBc @5MHz,Interferer -40dBc
-41 dBc @10MHz,Interferer -40dBc
16 Error Vector Magnitude (EVM) 17.5 % ( >-20dBm)
(@12.2k, 1DPDCH+1DPCCH)
17 Transmit OFF Power -15 dB@SF=4, 768kbps, multi-code
transmission
No Item GSM DCS & PCS
1 Sensitivity (TCH/FS Class II) -102dBm -102dBm
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
5Blocking Response Wanted Signal:-101dBm Wanted Signal :-101dBm
(TCH/FS Class II, RBER) Unwanted: Depend on Frequency Unwanted : Depend on Frequency
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2. PERFORMANCE
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4) Receiver - WCDMA Mode
No Item Specification
1Reference Sensitivity Level -106.7dBm(3.84M)
-25 dBm(3.84 MHz)
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)
-44 dBm/3.84MHz @f=2050 ~ 2095 &
2185 ~ 2230 MHz , band a)
UE@ =20dBm output power(class3)
-30 dBm/3.84MHz @f=2025 ~ 2050 &
5Out-band Blocking 2230~2255 MHz, band a)
UE@ +20dBm output power(class3)
-15 dBm/3.84MHz @f=1 ~ 2025 &
2255 ~ 12500 MHz, band a)
UE@ +20dBm output power(class3)
6Spurious Response -44dBm CW
UE@ +20dBm output power(class3)
-46 dBm CW@10MHz &
7Intermodulation Characteristic -46dBm/3.84MHz @20MHz
UE@ +20dBm output power(class3)
-57dBm@f=9KHz ~ 1GHz, 100K BW
-47dBm@f=1 ~ 12.5GHz, 1M BW
8Spurious Emissions -60dBm@f=1920MHz ~ 1980MHz, 3.84M BW
-60dBm@f=2110MHz ~ 2170MHz, 3.84M BW
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2. PERFORMANCE
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2.4 Current Consumption
(Stand by and Voice Call Test Condition : LCD backlight Off)
(VT Test Condition : Speaker off, LCD backlight On)
2.5 Antenna BAR
Stand by (Static) Stand by(Dynamic) Voice Call VT
WCDMA
300hrs/300hrs 220hrs/200hrs 140 Min 90 Min
(only mode/auto mode) (only mode/auto mode) (Tx=10 dBm) (Tx=10 dBm)
(DRX=2.56) (DRX=2.56)
Stand By (Static) - Voice Call
300 hrs/--- hrs 170 Min
GSM (only mode/auto mode) - (Tx=Max)
(Paging period =5)
Antenna Bar WCDMA GSM
BAR 3 RSCP>= -105 dBm RSSI >= -95dBm
and Ec/Io >= -12 dBm
BAR 2 -110 <= RSCP < -105 dBm -100 <= RSSI < -95 dBm
or -14 <= Ec/Io < -12 dBm
BAR 1 -113 <= RSCP < -110 dBm -105 <= RSSI < -100 dBm
or -17 <= Ec/Io < -14 dBm
BAR 0 RSCP < -113 dBm -110 <= RSSI < -105 dBm
or Ec/Io < -17 dBm
Network Notification Network Notification
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2.6 Battery BAR
2. PERFORMANCE
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Indication Voltage
During Idle state During Call state
BAR 3 -> 2 3.78 ± 0.05V 3.67 ± 0.05V
(call maintenance over 40min)
BAR 2 -> 1 3.67 ± 0.05V 3.57 ± 0.05V
(call maintenance over 10min)
BAR 1 -> 0 3.3V ± 0.05V 3.28V ± 0.05V
(Icon Blinking)
Low battery message BAR 1 -> 0
Low battery pop-up BAR 2 -> 1, display one time
Power OFF during call - 80s after Low battery message
Power OFF at stand-by 60s after Low battery message -
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2. PERFORMANCE
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2.7 Sound Pressure Level
2.8 Charging
• Charging Method: CC & CV (Constant Current and Constant Voltage)
• Maximum Charging Voltage: 4.2 V
• Normal Charging Current: 600 mA
• Normal Battery Capacity: 860 mAh
• Charging Time: Max 3 hours (except for trickle charging time)
• Full charging indication current (charging icon stop current): 140 mA
• Cut-off voltage:
Stand-by: 3.30 V,
Talk: 3.28 V
low temperature (under -10deg.): 3.00V
No Test Item Specification
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 ± 3 dB
10 Receiving Loudness Rating (RLR) Nor -1 ± 3 dB
Max -12 ± 3 dB
11 Side Tone Masking Rating (STMR) Min 25 dB
12 Echo Loss (EL) Min 40 dB
13 Sending Distortion (SD) Refer to Table 30.3
14 Receiving Distortion (RD) Refer to Table 30.4
15 Idle Noise-Sending (INS) Max -55 dBm0p
16 Idle Noise-Receiving (INR) Nor Under -45 dBPA
Max Under -40 dBPA
TDMA Noise
-. GSM: Power Level: 5
DCS/PCS: Power Level: 0
(Cell Power: -90 ~ -105 dBm)
17
-. 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 -62 dBm
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3. TECHNICAL BRIEF
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3.1 General Description
The L705i supports UMTS-800, UMTS-2100, GSM-900, DCS-1800, and PCS-1900 based
GSM/GPRS/UMTS. All receivers and the UMTS transmitter use the radioOne1Zero-IF architecture to
eliminate intermediate frequencies, directly converting signals between RF and baseband. The tri-
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 L705i is shown in Figure 1-1. One antenna collects
base station forward link signals and radiates handset reverse link signals. The antenna connects with
receive and transmit paths through a FEM(Front End Module) (plus two duplexers for UMTS high-band
and lowband operations).
1QUALCOMM’s branded chipset that implements a Zero-IF radio architecture..
3. TECHNICAL BRIEF
Fig 3.1 Block diagram of RF part
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The UMTS receive paths each include an LNA, an RF band-pass filter, and a downconverter that
translate the signal directly from RF-to-baseband using radioOne ZIF techniques. The high-band
UMTS receive path and low-band path are accommodated in the RTR6275 IC. The RFIC.s Rx analog
baseband outputs, for the receive chains, connect to the MSM IC. The UMTS and GSM Rx baseband
outputs share the same inputs to the MSM IC (at ADC1).
For the transmit chains, the RTR6275 IC directly translates the Tx baseband signals (from the MSM
device) to an RF signal using an internal LO generated by integrated on-chip PLL and VCO. The
RTR6275 IC outputs deliver fairly high-level RF signals that are first filtered by Tx SAWs and then
amplified by their respective UMTS PAs. The high- and low-band UMTS RF transmit signals emerge
from the RTR6275 transceiver.
In the GSM receive path, the received RF signals are applied through their band-pass filters and
down-converted directly to baseband in the RTR6275 transceiver IC. These baseband outputs are
shared with the UMTS receiver and routed to the MSM IC for further signal processing. The RFR6275
GSM/UMTS IC receiver baseband outputs share the same interface to the MSM IC input ADC as the
RTR6275 IC baseband outputs.
The GSM transmit path employs one stage of up-conversion and, in order to improve efficiency, is
divided into phase and amplitude components to produce an open-loop Polar topology:
1. The on-chip quadrature up-converter translates the GMSK-modulated signal or 8-PSK modulated
signal, to a constant envelope phase signal at RF
2. The amplitude-modulated (AM) component is applied to the ramping control pin of Polar power
amplifier from a DAC within the MSM
L705i power supply voltages are managed and regulated by the PM6650 Power Management IC. This
versatile device integrates all wireless handset power management, general housekeeping, and user
interface IC and higher-level handset functions. Key parameters such as under-voltage lockout and
crystal oscillator signal presence are monitored to protect against detrimental conditions. support
functions into a single mixed signal IC. It monitors and controls the external power source and
coordinates battery recharging while maintaining the handset supply voltages using low dropout,
programmable regulators.
The device’s general housekeeping functions include an ADC and analog multiplexer circuit for
monitoring on-chip voltage sources, charging status, and current flow, as well as user-defined off-chip
variables such as temperature, RF output power, and battery ID. Various oscillator, clock, and counter
3. TECHNICAL BRIEF
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3. TECHNICAL BRIEF
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3.2 GSM Mode
3.2.1 GSM Receiver
The Dual-mode L705i’s receiver functions are split between the three RFICs as follows:
• UMTS-800 operation uses the RFR6275 Receiver ICs to implement the receive signal path,
accepting an RF input and delivering analog baseband outputs (I and Q).
• UMTS-2100, GSM-900, DCS-1800, and PCS-1900 modes use the RTR6275 IC only. Each mode
has independent front-end circuits and down-converters, but they share common baseband circuits
(with only one mode active at a time). All receiver control functions are beginning with SBI2-
controlled parameters.
RF Front end consists of antenna, antenna switch module(D2024) which includes four RX saw
filters(GSM850, GSM900, DCS and PCS). The antenna switch module allows multiple operating
bands and modes to share the same antenna. In L705i, a common antenna connects to one of eight
paths: 1) UMTS-800 Rx/Tx, 2) UMTS-1900 Rx/Tx, 3) GSM-850 Rx, 4) GSM-900 Rx, 5) GSM-850
GSM-900 Tx, (Low Band Tx’s share the same path) 6) DCS- 1800 Rx, and 7) DCS-1800,PCS-1900
Tx(High Band Tx’s share the same path), 8) PCS- 1900 Rx. UMTS operation requires simultaneous
reception and transmission, so the UMTS Rx/Tx connection is routed to a duplexer that separates
receive and transmit signals. GSM850/GSM900, DCS, and PCS operation is time division duplexed,
so only the receiver or transmitter is active at any time and a frequency duplexer is not required.
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.
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The GSM900, DCS, and PCS receiver inputs of RTR6275 are connected directly to the transceiver
frontend circuits(filters and antenna switch module). GSM900, DCS, and PCS receiver inputs are
similar to the RFR6275 UMTS Rx input in that they also use differential configurations to improve
common-mode rejection
Since GSM900, DCS, and PCS signals are time-division duplex (the handset can only receive or
transmit at one time), switches are used to separate Rx and Tx and second-order non-linearity
performance. The balance between the complementary signals is critical and must be maintained from
the RF filter outputs all the way into the IC pins
signals in place of frequency duplexers - this is accomplished in the switch module.
The GSM900, DCS, and PCS receive signals are routed to the RTR6275 through band selection filters
and matching networks that transform single-ended 50-Ω •sources to differential impedances optimized
for gain and noise figure. Similar to the RFR, the RTR input uses a differential configuration to improve
second-order inter-modulation and common mode rejection performance. The RTR6275 input stages
include MSM-controlled gain adjustments that maximize receiver dynamic range.
The amplifier outputs drive the RF ports of the quadrature RF-to-baseband downconverters. The
downconverted baseband outputs are multiplexed and routed to lowpass filters (one I and one Q)
having passband and stopband characteristics suitable for GMSK or 8-PSK processing. These filter
circuits include DC offset corrections. The filter outputs are buffered and passed on to the MSM6280 IC
for further processing (an interface shared with the RFR6275 UMTS receiver outputs
3. TECHNICAL BRIEF
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Switch Mode CTRL1 CTRL2 CTRL3
GSM850/EGSM TX 1 0 1
PCN/PCS TX 0 1 1
WB850 0 1 1
WB1900 0 0 1
WB2100 1 0 1
GSM850 RX 0 0 0
EGSM RX 1 0 0
PCN RX 1 1 0
PCS RX 0 1 0
All Off 1 1 1
ANENNA SWITCH MODULE LOGIC
Table 3.2.1 Antenna Switch Module Control logic
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Only for training and service purposes
3. TECHNICAL BRIEF
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Fig 3.2.1 RTR6275 RX feature
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