W215 W218 Circuit Description, ---SCHEMATY---GSM
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W215/W218 Level 3 Circuit Description 25 April 2007 V1.0 W215/W218 Level 3 C Index 1 Receive .................................................................................................... 4 1.1 Band selection...........................................................................................4 1. 2 Demodulation............................................................................................5 1. 3 Audio Codec..............................................................................................6 1. 3 .1 Voice Downlink Patch .................................................................................................. 7 1. 4 Earpiece Receiver......................................................................................7 1. 5 Headset....................................................................................................7 1. 6 Speaker Phone..........................................................................................7 1. 7 Data Download Receive Path......................................................................8 2 Transmit .................................................................................................. 8 2.1 Audio (Voice uplink Patch).......................................................................... 9 2.2 Data Download Transmit Path.................................................................... 9 2.3 Stereo Audio Path...................................................................................... 9 2.4 Modulation ................................................................................................................... 10 2.5 RF TX PA ............................................................................................... 12 2.6 TX PA Power Control in SKY77318 .......................................................... 13 3 Triton-Lite Monitoring ADC .................................................................... 14 4 Baseband Serial Port (BSP) .................................................................... 15 5 Microcontroller Serial Port (USP) ........................................................... 15 6 General purposes I/O (GPIO)................................................................. 15 7 TFT LCD Display...................................................................................... 17 7.1 Display Backlights ...................................................................................................... 18 7.2 Image Processor......................................................................................18 7.3 Camera Module........................................................................................19 8 32kHz RTC .............................................................................................. 19 9 SIM Card Circuit ..................................................................................... 19 9.1 SIM Card Supply Voltage Generation.........................................................20 10 Keypad................................................................................................... 20 10.1 Keypad Matrix.........................................................................................21 11 Vibrator circuit ....................................................................................... 21 Motorola Proprietary Information - 2 - W215/W218 Level 3 C 12 Memory .................................................................................................. 21 13 Power ..................................................................................................... 22 13.1 Low-Dropout Voltage Regulators............................................................... 22 13.2 Power Down Methods.............................................................................. 23 14 Sleep Module .......................................................................................... 23 14.1 Sleep Up Sequence.................................................................................. 24 14.2 Sleep off Sequence.................................................................................. 24 15 Power Tree ............................................................................................. 25 16 Charging Circuit and External Power ..................................................... 25 16.1 Battery Support....................................................................................... 25 16.2 Charger Support...................................................................................... 25 Motorola Proprietary Information - 3 - W215/W218 Level 3 C 1 Receive 1.1 Band selection The radio frequency signal is received from internal PIFA-type antenna. Received GSM RF signal enters to PCB through the RF switch JP201 . At this moment the T/R switch SW201 is switched to RX mode to let the signal input to next stage. Then the signal goes into SAW filter, BF201 and BF202 , which reject out-band signal and transfer the signal from single-end to balanced. And the matching circuits between T/R switch and SAW filter reduce the unwanted RF signal reflection and provide a flat frequency response in the operation band. Finally the received signal will fed into Locosto Plus U101 DRP core through a balanced MLCC matching network. The following table describes the control voltages of T/R switch and PA: W215 SW_LO_TX PIN 5 of T201 SW_HI_TX PIN 2 of T201 PA_EN TP201 VAPC PIN 20 of U201 BS1 TP202 Standby Low x Low Low x RX EGSM900 Low Low Low Low Low RX DCS1800 Low Low Low Low High TX GSM900 High High High High Low TX DCS1800 High High High High High The RF signal is received by internal antenna or by RF plug, and the signal is passing through the RF switch JP201 and then fed into T/R switch. The low band (GSM900) RX received signal is transmitted from SW201 ( Pin 11 ) and input to low-band SAW filter BF201 , while the high band (DCS1800) RX received signal from SW201 ( Pin 1 ) and then input to high-band SAW filter BF202 . The last stage of RX on PCB is Locosto U101 ( Loocsto-Plus ), and the DRP process will make the signal into binary data. Figure 1: Locosto TX/RX Paths Description Motorola Proprietary Information - 4 - W215/W218 Level 3 C 1.2 Locosto RX Mode Formatiert: Nummerierung und Aufzählungszeichen Figure 2: Locosto RX Signal Process As described in Figure 2, when the RF signal is input to Locosto, it will be amplified by a differential LNA in advance, in order to obtain a better NF in the last receiving stage. And then it will be turned into discrete IF signal by a high-speed mixer. After passing through a filter and an A/D converter, the discrete signal will become digital signal and then input to Locosto core to do DSP process. The detail RX signal route is depicted as below: Motorola Proprietary Information - 5 - [ Pobierz całość w formacie PDF ] |