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3. TECHNICAL BRIEF
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3.3 UMTS Mode
3.3.1 Receiver
The UMTS duplexer receiver output is routed to LNA circuits within the RTR6275 device. The UMTS Rx
input is provided with an on-chip LNA that amplifies the signal before a second stage filter that provides
differential downconverter. This second stage input is configured differentially to optimize second-order
intermodulation and common mode rejection performance. The gain of the UMTS frontend amplifier and
the UMTS second stage differential amplifier are adjustable, under MSM control, to extend the dynamic
range of the receivers. The second stage UMTS Rx amplifiers drive the RF ports of the quadrature RF-
tobaseband 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 up-
converter 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 F
LO
to equal F
RF
, and the RTR6275 IC design
achieves this without allowing F
VCO
to equal F
RF
.
The RTR6275 IC is able to support UMTS 2100/1900 and UMTS 850 mode transmitting. This design
guideline shows only UMTS 2100 applications.
Содержание U250
Страница 1: ...Date June 2007 Issue 1 0 Service Manual Model U250 KU250 Service Manual U250 KU250 ...
Страница 3: ... 4 ...
Страница 20: ...3 TECHNICAL BRIEF 21 Fig 1 2 RTR6275 RX feature ...
Страница 23: ...3 TECHNICAL BRIEF 24 Figure 1 4 RTR6275 IC functional block diagram WCDMA_2100_TX WCDMA_2100_RX ...
Страница 28: ...3 TECHNICAL BRIEF 29 Figure1 7 PM6650 Block Diagram ...
Страница 41: ...3 TECHNICAL BRIEF 42 Table 1 2 Description of RF configurations ...
Страница 45: ...3 TECHNICAL BRIEF 46 Figure 1 12 PM6650 Functional Block Diagram ...
Страница 72: ...4 TROUBLE SHOOTING 73 4 1 RF Component 4 TROUBLE SHOOTING LGMC ...
Страница 73: ...4 TROUBLE SHOOTING 74 Block Diagram Block Ref Name UMTS Part Name Function Comment ...
Страница 77: ...4 TROUBLE SHOOTING 78 Check C312 of PMIC U300 Check R213 of MSM U201 T ...
Страница 81: ...4 TROUBLE SHOOTING 82 ...
Страница 84: ...4 TROUBLE SHOOTING 85 ...
Страница 85: ...4 TROUBLE SHOOTING 86 4 7 Checking GSM Block 1 3 2 ...
Страница 87: ...4 7 3 Checking RF Tx level 4 TROUBLE SHOOTING 88 ...
Страница 90: ...4 TROUBLE SHOOTING 91 ...
Страница 97: ...4 TROUBLE SHOOTING 98 R313 Q301 Q302 Q300 Charging part Main PCB Front ...
Страница 107: ...4 TROUBLE SHOOTING 108 R422 R421 U401 ...
Страница 109: ...4 TROUBLE SHOOTING 110 C401 C402 R406 C407 CN401 ...
Страница 111: ...4 TROUBLE SHOOTING 112 Analog Switch Audio Amp SPK ...
Страница 113: ...4 TROUBLE SHOOTING 114 MIC400 C417 R424 ...
Страница 115: ...4 TROUBLE SHOOTING 116 Ear_Sense_N MIC Input ...
Страница 117: ...4 TROUBLE SHOOTING 118 VPWR MOTOR_PWR ...
Страница 133: ...6 BLOCK DIAGRAM 134 6 1 GSM UMTS RF Block 6 BLOCK DIAGRAM Fig 2 1 U250 KU250 RF Functional Block Diagram ...
Страница 134: ...6 BLOCK DIAGRAM 135 Table 2 1 RF Block Component ...
Страница 136: ...6 BLOCK DIAGRAM 137 6 2 2 Memory Interface Fig 2 3 Memory Interface Diagram ADDRESS 14 0 ...
Страница 137: ...6 BLOCK DIAGRAM 138 6 2 3 USB UART SIM JTAG Interface Fig 2 4 USB UART SIM JTAG Interface ...
Страница 139: ...6 BLOCK DIAGRAM 140 6 2 4 Placement Top Side LGMC ...
Страница 140: ...6 BLOCK DIAGRAM 141 Bottom Side LGMC ...
Страница 141: ... 142 ...
Страница 146: ... 147 LGMC 8 PCB LAYOUT U250 KU250 ...
Страница 147: ... 148 LGMC 8 PCB LAYOUT U250 KU250 ...
Страница 157: ... 158 ...
Страница 174: ...Note ...
Страница 175: ...Note ...