ERICSSON EF738 TechDes
Technical Description
Ericsson Mobile Phone EF738
Technical Description
2
Technical Description
Contents
Overview __________________________________________ 7
Basic Building Blocks ______________________________________ 8 Transceiver Block Diagram _________________________________ 9 PCB ____________________________________________________ 10
Mechanical Design __________________________________11
Man Machine Interface (MMI)_______________________ 12
Keypad _________________________________________________ 12 Display _________________________________________________ 12 Acoustic Signals __________________________________________ 12 Top LED Indicator _______________________________________ 12
Radio Design ______________________________________ 13
General Overview ________________________________________ 13
Antenna Connector ___________________________________________ 13 Antenna Filters ______________________________________________ 13 Receiver Part________________________________________________ 14 Receiver Front End ________________________________________ 14 IF Part __________________________________________________ 14 Receiver Back-End ________________________________________ 15
Synthesizer _________________________________________________ 16 Programming _____________________________________________ 16 Power ___________________________________________________ 16 Lock Detect ______________________________________________ 16 VCTCXO __________________________________________________ 17 Transmitter _________________________________________________ 18 TX Blocks _______________________________________________ 18 MALIN ____________________________________________________ 19 TX-IF VCO ______________________________________________ 19 TX Mixer ________________________________________________ 19 TX Modulation ___________________________________________ 19 TX-IF Frequency Control ___________________________________ 19 Programmable Prescaler ____________________________________ 19
Power and Charging Design _________________________ 20
Regulators ______________________________________________ 20 Reset ___________________________________________________ 21 On/Off Control __________________________________________ 21 Charging Circuitry _______________________________________ 21 Transient/ESD Protection__________________________________ 22 Off Current Draw ________________________________________ 22
User Interface _____________________________________ 23
Illumination _____________________________________________ 23 Buzzer __________________________________________________ 23 LCD Display_____________________________________________ 23 Keypad _________________________________________________ 23
Continued on next page
3
Technical Description
Logic Design ______________________________________ 24
GUSTAV ________________________________________________24
Circuit Description ___________________________________________ 24 6303 ____________________________________________________ 24 ROM ___________________________________________________ 24 RAM ___________________________________________________ 24 Bus Interface _____________________________________________ 24 Decoder _________________________________________________ 25 Serial Interface ____________________________________________ 25 External Ports_____________________________________________ 25 WatchDog On/Off _________________________________________ 25 IFC _____________________________________________________ 25 BAR ____________________________________________________ 25 Clock Generator ___________________________________________ 25 Internal Ports _____________________________________________ 26 Modem __________________________________________________ 26 Baud Clock ______________________________________________ 26 I2C Controller ____________________________________________ 26
FLASH EPROM __________________________________________26 EEPROM ________________________________________________26
Audio Design ______________________________________ 27
Receive Audio Circuit Description ___________________________27
Receive Audio Interface _______________________________________ 27 De-Emphasis Network ________________________________________ 27 RXSENSE Programmable Gain Stage ____________________________ 27 Receive Bandpass Filter _______________________________________ 27 Expandor Gain ______________________________________________ 28 RX HF Attenuation ___________________________________________ 28 RX Volume Control __________________________________________ 28 EARSENS Programmable Gain Stage ____________________________ 28 Externally Programmable Gain Stage_____________________________ 28 Earpiece Driver ______________________________________________ 29 AFMS _____________________________________________________ 29
Transmit Audio Circuit Description __________________________29
ATMS _____________________________________________________ 29 Microphone Input ____________________________________________ 29 Soft Limit __________________________________________________ 30 INPSENSE Programmable Gain Stage____________________________ 30 Transmit Bandpass Filter ______________________________________ 30 TX HF Attenuator ____________________________________________ 30 Compressor _________________________________________________ 30 Pre-emphasis ________________________________________________ 30 Hard Limit__________________________________________________ 31 Transmit Lowpass Filter _______________________________________ 31 AUDIODEV Programmable Gain Stage __________________________ 31 Summing Amplifier __________________________________________ 31 TXSENSE Programmable Gain Stage ____________________________ 31
Low Voltage Detect Circuit _________________________________31
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4
Technical Description
RX and TX Sat Circuits ___________________________________ 32
RX SAT Filter ______________________________________________ 32 RX SAT Schmit Trigger_______________________________________ 32 TX SAT Filter_______________________________________________ 32 TX SATDEV Programmable Gain Stage __________________________ 32
8Kbit/s Manchester Data Circuit ____________________________ 32
Data Filter __________________________________________________ 32 DATADEV Programmable Gain Stage ___________________________ 32
HandsFree Circuit ________________________________________ 32
Software Design ___________________________________ 33
Power Down Control______________________________________ 33 Timing and Operation_____________________________________ 33
Main Modes of Operation______________________________________ 33 Power Saving Sleep Function___________________________________ 33
Software Assignments _____________________________________ 33
Technical Specifications _____________________________ 34
General ____________________________________________________ 34 Transmitter _________________________________________________ 34 Receiver ___________________________________________________ 34
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Technical Description
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Technical Description
Overview
The Ericsson EF738 Mobile Phone is a small, lightweight phone operating at 3.8V. It is a class 4 cellular telephone that is fully compatible with the ETACS system with extended frequencies.
The EF738 includes the following three exterior parts:
•telephone section (incl. keypad, character display, earpiece, microphone and flip)
•removable battery
•removable antenna
Figure 1: The Ericsson Mobile Phone EF738
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Technical Description
Basic Building Blocks
The diagram below shows the basic building blocks:
ANTENNA
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DUPLEXER
RX |
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SYNTHESIZER |
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TX |
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SYSTEM |
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LOGIC |
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AUDIO |
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USER
BATTERY ACCESSORIES
INTERFACE
Figure 2: Basic Building Blocks
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Technical Description
Transceiver Block Diagram
The transceiver (transmitter/receiver) consist of a digital part that controls and supervises transmission/reception on the radio channel. It also handles keyboard, display and protocol transmission to the MTX (Mobile Telephone eXchange). The audio part controls audio signals for earphone, microphone and modem.
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TRANSMITTER |
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CPU |
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FREQ. GENERATOR |
control bus |
MEMORIES |
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MOD. RECEIVER |
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On/Off |
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KEYPAD |
M M I |
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AUDIO PROCESSING |
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MICRO/LOUDSPKR |
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ATMS/AFMS |
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Figure 3: Transceiver Block Diagram
9
Technical Description
PCB
The printed circuit board is a 6-layer PCB where all components are located in layer 1 (primary side) and layer 6 (secondary side).
Layers 2 and 5 are ground planes and layers 3 and 4 are used for signal conducting.
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Primary Side |
Secondary Side |
ANT |
DUPLEXER |
BUZZER |
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RECEIVER |
VCO |
VOL |
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TRANSMITTER |
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VOL |
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MALIN |
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IF PART |
VCTCXO |
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BAT |
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CON |
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BERT- |
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INDY |
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MIA |
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KEYPAD |
GUSTAV |
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ANTON |
FLASH |
EE- |
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PROM |
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SYSTEM CONNECTOR |
SYSTEM CONNECTOR |
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Figure 4: PCB LayOut
10
Technical Description
Mechanical Design
The phone is designed as a ‘brick’ with a mechanical assembly consisting mainly of:
•plastic front cover
•plastic rear cover
•plastic flip
•keyboard
•system connector
•LCD light guide
•metallic plastic for PCB shielding
It has been designed for easy assembly with 6 screws.
An optional clip can be mounted into the rear cover.
Figure 5: Mechanical Assembly
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