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
Continued on next page
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
5
Technical Description
6
Overview
Technical Description
The Ericsson
It is a class 4 cellular telephone that is fully compatible with the ETACS system
with extended frequencies.
EF738
The
telephone section
•
•
removable
•
removable
EF738
includes the following three exterior parts:
Mobile Phone is a small, lightweight phone operating at 3.8V.
(incl. keypad, chara cter di splay, earpiece, microphone and flip)
battery
antenna
Figure 1: The Ericsson Mobile Phone EF738
7
Technical Description
Basic Building Blocks
The diagram below shows the basic building blocks:
ANTENNA
&
DUPLEXER
RX SYNTHESIZER TX
SYSTEM
BATTERY ACCESSORIES
Figure 2: Basic Building Blocks
LOGIC
USER
INTERFACE
AUDIO
8
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.
RADIO
TRANSMITTER
FREQ. GENERATOR
MOD. RECEIVER
mo d discr
AUDIO PROCESSING
MICRO/LOUDSPKR
Figure 3: Transceiver Block Diagram
control bus
LOGIC
CPU
MEMORIES
On/Off
KEYPAD
DISPLAY
ATMS/AFMS
MMI
E
X
T
E
R
N
A
L
C
O
N
N
E
C
T
O
R
9
Technical Description
PCB
The printed circuit board is a 6-layer PCB where all comp onents 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.
ANT
RECEIVER
GUSTAV
Primary Side
IF PART
BERT-
DUPLEXER
VCO
INDY
MALIN
VCTCXO
BAT
CON
ANTON
Secondary Side
BUZZER
VOL
TRANSMITTER
VOL
MIA
KEYPAD
FLASH
SYSTEM CONNECTOR
EE-
PROM
Figure 4: PCB LayOut
SYSTEM CONNECTOR
10
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.
Technical Description
Figure 5: Mechanical Assembly
11
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