ERICSSON AF738, AF778 Technical Description CH2

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Technical Description EN/LZB 119 2506 R1A

Chapter 2

Technical Description

Ericsson Cellular Phone AF738

AF778

EN/LZB 119 2506 R1A Technical Description

SUBJECT .................................................................................... PAGE

General ................................................................................................................... 2-1

Mechanical........................................................................................................2-2

Table 2-1. Phone Dimensions ............................................................................2-2

Keypad..............................................................................................................2-3

Figure 2-1.Keypad.............................................................................................2-3

Side Volume Keys.............................................................................................2-4

Figure 2-2. Side Volume Keys...........................................................................2-4

LCD..................................................................................................................2-4

Figure 2-3. LCD Display ...................................................................................2-4

Table 2-2. LCD Display Areas...........................................................................2-4

Top Indicator.....................................................................................................2-5

Table 2-3. Top Indicator Functions....................................................................2-5

Vibrator Motor (AF778 Only)............................................................................2-6

Retractable Antenna ..........................................................................................2-6

1/4 Wave Antenna Operation.........................................................................2-6

Figure 2-4. AF778 1/4 Wave Antenna Connections............................................2-7

1/2 Wave Antenna Operation (AF778)...........................................................2-7

Figure 2-5.1/2 Wave Antenna Connections........................................................2-8

Transceiver PCB and Component Layout............................................................. 2-9

Major Components................................................................................................2-10

Figure 2-6. PCB Component Layout................................................................2-10

Table 2-4. Component Table............................................................................ 2-11

Figure 2-7. Block Diagram ..............................................................................2-13

Radio Section.........................................................................................................2-15

General............................................................................................................ 2-15

Table 2-5. Frequencies..................................................................................... 2-15

Duplexer..........................................................................................................2-16

Receiver..........................................................................................................2-16

Receive Front End .......................................................................................2-17

IF Section.................................................................................................... 2-17

Synthesizer......................................................................................................2-18

VCTCXO.................................................................................................... 2-18

BERTINDY.................................................................................................2-19

RX (Main) Synthesizer ................................................................................2-19

TX (Auxiliary) Synthesizer..........................................................................2-20

MALIN .......................................................................................................2-20

Transmitter......................................................................................................2-20

Power Amplifier.......................................................................................... 2-20

Technical Description EN/LZB 119 2506 R1A

SUBJECT......................................................................................................... PAGE

Logic Section......................................................................................................... 2-21

Processor/Control Interface............................................................................. 2-21

GUSTAV.................................................................................................... 2-22

6303 Microprocessor................................................................................... 2-22

ROM .......................................................................................................... 2-22

RAM .......................................................................................................... 2-22

Bus Interface............................................................................................... 2-22

Decoder...................................................................................................... 2-22

Serial Interface ............................................................................................ 2-22

External Ports ............................................................................................. 2-22

Watchdog On/Off........................................................................................ 2-23

Beep, Alarm, Ring (BAR)........................................................................... 2-23

Clock Generator .......................................................................................... 2-23

Silent Ring (AF778 Only)........................................................................... 2-23

Internal Ports .............................................................................................. 2-23

Modem ....................................................................................................... 2-24

Baudclock................................................................................................... 2-24

Memories........................................................................................................ 2-24

RAM .......................................................................................................... 2-24

ROM .......................................................................................................... 2-24

EPROM (Flash).......................................................................................... 2-25

EEPROM.................................................................................................... 2-25

User Interface ................................................................................................. 2-26

LCD ........................................................................................................... 2-26

Keyboard.................................................................................................... 2-26

Buzzer ........................................................................................................ 2-26

Illumination ................................................................................................ 2-27

Vibrator Motor (AF778 Only)..................................................................... 2-27

Audio (Baseband) Section............................................................................... 2-27

Receive Audio ............................................................................................ 2-27

Transmit Audio........................................................................................... 2-27

Power Supplies............................................................................................... 2-28

Regulators................................................................................................... 2-28

Reset........................................................................................................... 2-28

On/Off Control............................................................................................ 2-28

Transient/ESD Protection............................................................................ 2-29

Charging Circuit............................................................................................. 2-29

Rapid Charging........................................................................................... 2-30

Figure 2-8. Rapid Charging ............................................................................. 2-30

Trickle Charging......................................................................................... 2-30

Connections On The Transceiver Board.............................................................. 2-31

Antenna Connector......................................................................................... 2-31

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EN/LZB 119 2506 R1A Technical Description

SUBJECT.......................................................................................................... PAGE

Battery Contacts.............................................................................................. 2-31

Speaker Connector...........................................................................................2-31

LCD Contacts.................................................................................................. 2-31

Microphone Connector....................................................................................2-31

Vibrator Connector (AF778 Only) ...................................................................2-31

Antenna Ground Strap (AF778 Only)...............................................................2-31

System Connector............................................................................................2-32

Figure 2-9. System Connector.......................................................................... 2-32

Table 2-6. System Connector Signals ...............................................................2-32

Specifications.........................................................................................................2-33

Technical Description EN/LZB 119 2506 R1A

AF778

END PWR

General

The Ericsson AF738 and AF778 cellular telephones are small, lightweight phones operating at 4.8v, powered by a 4-cell Nickel Metal Hydride (NiMH) battery. They are class III cellular telephones for use with the AMPS cellular network.

Features of the phone include:

• Compact and lightweight

• Retractable Antenna

• Power-on greeting

• Multilingual with Language menus

• Built-in charging circuitry

• Authentication capable (system dependent)

• Caller line ID* (CLI)

• Voice mail message waiting indicator* (MWI)

• Negative SID Navigation

• Multiple NAMS (up to four)

• Multiple memory locations:

• Standard memory

• Last 10 Numbers dialed

• 1 Last 0 Caller Line IDs (CLI)

∗

• 5 Scratch Pad Memory Locations

• 5 Secure Memory Locations

• Dual-tone multi-frequency (DTMF) dialing

• RSSI and battery capacity indicators

• Ability to connect to external handsfree equipment

• Meets FCC Hearing Aid Compatibility Standards

• Electronic Lock/Call Restrictions

• Ring tone and volume selection

• System selection

• Different answering methods

• Microphone volume selection

• Auto retry on system busy

• Backlight selection

• Minute Minder Selection

• Auto area code

• Emergency numbers

SEND

∗

Requires software version R5A or higher

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EN/LZB 119 2506 R1A Technical Description

• Call time counters

• Silent call alert with vibrator (AF778 only)

• ½ wave up, ¼ wave down antenna

Mechanical

Refer to Table 2-1 for phone dimensions. The telephone consists of:

• A transceiver

• A removable battery

• A removable, retractable antenna

• A removable, active flip

Table 2-1. Phone Dimensions

English Metric

AF738 AF778 AF738 AF778

Length 4.17 in. 4.17 in. 106 mm 106 mm Width 1.97 in. 1.97 in. 50 mm 50 mm Thickness .94 in. .94 in. 24 mm 24 mm Weight

(w/battery)

4.8 oz. 4.9 oz. 137 g 139 g

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Technical Description EN/LZB 119 2506 R1A

The transceiver consist of:

• Front cover (with speaker)

• Back cover

• Keypad

• Printed circuit board (PCB)

• LCD/lightguide assembly

• Vibrator (AF778 only)

Keypad

The keypad is rubber with soft keys. See Figure 2-1. It is backlit, which makes it possible to operate the phone in the dark. The backlight function has four possible settings:

• On 10 seconds

• On 20 seconds

• On (when connected to external power only)

• Off

The END/PWR/NO key is not scanned, as are the other keys. It is connected to a power switch such that microprocessor power is forced on when this key is held down. The microprocessor can also see this key indirectly to implement the OFF function.

SEND

END PWR

YES

MEM CLR MENU

Figure 2-1. Keypad

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EN/LZB 119 2506 R1A Technical Description

READY

Side Volume Keys

See Figure 2-2. The volume keys are separate from the main keypad. They are push button switches mounted on the side of the phone near the upper left corner of the LCD.

SIDE VOLUME KEYS

Figure 2-2. Side Volume Keys

LCD

The phone has a 1-line LCD containing icons as well as numbers and alpha characters. See Figure 2-3 and Table 2-2.

Figure 2-3. LCD Display

Table 2-2. LCD Display Areas

Fig.

Ref. Description Function

1 Number/Character Display Displays number or character entered 2 Battery Strength Icon Displays relative strength of battery 3 Signal Strength Indicator Displays signal strength (up to 5 bars)

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Technical Description EN/LZB 119 2506 R1A

Top Indicator

A multi-color light emitting diode (LED) is located on the top front of the phone. Refer to Table 2-3.

Table 2-3. Top Indicator Functions

Light Indicates

Green - slow blink Ready. Phone is ready to make/receive calls. Green - fast blink There is an incoming call or you have answered an

incoming call. Green - steady Battery is charging and phone is ON. Red - blinking Battery power is low. Orange – Slow blink* Alert Option (Menu 16) is set to vibrate only.

Orange – Fast blink*

Orange – Steady* Alert option – vibrator only. Battery charging. No light

* AF778 Only

Alert option (Menu 16) is set to vibrate only, and there is

an incoming call, or you have answered and incoming

call.

Phone is OFF, no signal is available, or phone is in

CHARGING ONLY mode.

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EN/LZB 119 2506 R1A Technical Description

Vibrator Motor (AF778 Only)

The AF778 cellular phone has a vibrating motor as an option for silent ring indication. When the vibrating motor is activated (Menu 16), the unit will vibrate three times when receiving an incoming call. It will also vibrate when the phone is first turned on.

Retractable Antenna

Both the AF738 and the AF778 feature a retractable antenna. The AF738 is 1/4 wave in both the up (extended) and the down (retracted) positions. The AF778 is 1/4 wave in the down position and 1/2 wave in the up position.

The AF778 uses a new design consisting of a molded antenna base with a metallic contact ferrule, and a retractable whip consisting of a helical coil, an overmolded whip cap, and an exposed metallic upper contact ring.

This design allows the antenna to operate in 1/4 wave and 1/2-wave modes while requiring a single RF feed.

1/4 Wave Antenna Operation

In the retracted position, the AF778 operates in 1/4 wave mode. The helical coil contacts directly to the ferrule on the antenna base. The contact ferrule makes a direct connection to the RF feed on the antenna connector. This in turn provides a path to the RF feed point on the PCB. The end of the whip is grounded to the PCB via a grounding clip. See Figure 2-4.

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Technical Description EN/LZB 119 2506 R1A

PCB

HELICAL COIL

ANTENNA BASE

CONTACT FERRULE

GROUND CONTACT (NOT CONNECTED WHEN RETRACTED)

ANTENNA MAST

BOTTOM CRIMP CONTACT (ANTENNA GROUND)

Figure 2-4. AF778 1/4 Wave Antenna Connections

1/2 Wave Antenna Operation (AF778)

The helical connection to the PCB is broken when the antenna is extended. The contact ferrule, however, remains in contact with the RF feed contact on the PCB. The connection from the RF contact on the PCB and the antenna is made (via a capacitive coupling) through a dielectric insulating material to the antenna rod. Since the antenna mast is connected to the top helical coil, the antenna becomes an effective 1/2-wave antenna.

The bottom crimp contact on the antenna mast mates with shunt inductor-to-ground contact when the antenna is extended. To prevent the bottom crimp from shorting to the RF feed, the overmolded stepped insulator provides insulation between the two points. The coaxial connection to the NiTi rod and the shunt inductor make up the matching network. See Figure 2-5.

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EN/LZB 119 2506 R1A Technical Description

PCB

Figure 2-5. 1/2 Wave Antenna Connections

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Technical Description EN/LZB 119 2506 R1A

Transceiver PCB and Component Layout

The transceiver consists of one PCB for both the RF and logic sections. The board is a six layer PCB. Layers two and five act as ground planes, while layer three serves as a plane for signal conductors.

The basic circuits of the phone are:

• RF Section

Receives and generates the RF signals needed to establish a duplex link between the cellular mobile and base station

• Logic Section:

Digital Logic Controls and supervises transmission/reception on the radio channel. It also handles keyboard, display, and protocol transmission to the base station.

Analog Logic (Audio) Handles audio signals for earpiece, microphone, and the modem.

See Figure 2-6. Most of the components are located on the primary side of the PCB. A few surface mount devices (SMDs) are located on the secondary side, such as the buzzer and Power Amplifier (PA). Pads for the keyboard are also on the secondary side.

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EN/LZB 119 2506 R1A Technical Description

Secondary Side

SYSTEM

CONNECTOR

MICROPHONE

VIBRATOR CONNECTOR

LCD

CONTACTS

DISPLAY

BACKLIGHT

KEYPAD

HALL-EFFECT

Major Components

The circuitry is based mainly on CMOS components. This minimizes current consumption so the battery may last longer. The components are in SMD packages, which are more cost/size effective than components mounted through the board.

To minimize the size of the board and number of components, Application Specific Integrated Circuits (ASICs) have been designed and used. These, along with other major components, are shown in Figure 2-6 and listed in Table 2-4.

SHIELD CAN OUTLINE

X301

Z211

Z231

BATTERY CONTACTS

ANTENNA STRAW GROUND STRAP X704 (AF778 ONLY)

Z300

N211

G401

Z204

N401

Z206

N201

N702

N402

N703 N705

D603

D601

N500

D602

VOLUME SWITCHES

B401

N701

CONTACTS (17)

(AF778 ONLY)

X703

SPEAKER

B502

H802

BUZZER

N301

SWITCH FOR FLIP

Primary Side

X701

(10)

LEDS

Figure 2-6. PCB Component Layout

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Technical Description EN/LZB 119 2506 R1A

Table 2-4. Component Table

Section Reference Name Function

Radio B401 Crystal Reference oscillator, 14.85 MHz,

heart of discrete VCTCXO circuit G401 VCO Main Voltage Control Oscillator N201 IF IC RX Back end N211 Annika RX Front end N301 PA Power Amplifier (GaAs FET IC) N401 Malin TX mixer, TX VCO, TX/RX

buffers N402 Bertindy Radio interface to Logic,

synthesizers N702,

Voltage Regulators N703, N705 Z204 450 KHz Filter Z206 2nd IF Filter Z211 Filter RX Z231 45 MHz

1st IF Filter

Filter

Z300 Duplexer TX/RX Filter

Logic/ Baseband

D601 Flash

EPROM

Memory - system program

D602 EEPROM Memory - Customer data D603 Gustav Master logic control (includes

microprocessor) N500 Anton Audio control N701 Mia Charging functions

Connectors B502 Speaker

Makes contact with speaker

Connector H802 Buzzer Emits ringer, alert tones X301 Antenna

Makes contact with antenna

Connector X701 System

Connector

Connects PCB to user interfaces, outside peripherals, charging functions.

X703 Vibrator

AF778 only

Connector X704 Antenna

AF778 only Straw Groundstrap

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EN/LZB 119 2506 R1A Technical Description

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Technical Description EN/LZB 119 2506 R1A

Figure 2-7. Block Diagram

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EN/LZB 119 2506 R1A Technical Description

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Technical Description EN/LZB 119 2506 R1A

Radio Section

General

See Figure 2-5. This section includes information about the following:

• Duplexer

• Receiver

Receive front end IF section

• Synthesizer

• Transmitter

Refer to Table 2-5. The radio section of the phone contains all circuitry necessary for receiving and transmitting the RF signal. The radio operates in the AMPS frequency bands. These frequencies make up 832 duplex channels.

Table 2-5. Frequencies

Type Measurement

Transmit frequencies 824.04 to 848.97 MHz Receive frequencies 869.04 to 893.97 MHz Duplex separation 45 MHz Channel spacing 30 KHz

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EN/LZB 119 2506 R1A Technical Description

Duplexer

See Figure 2-7. The duplex filter consists of a three-pole TX filter section and a fourpole RX filter section.

The TX filter section suppresses wide band noise evolving from the VCO and the power amplifier on RX frequencies.

The RX filter section suppresses the transmitter signal. This suppression must be at a level low enough not to overdrive the receiver front-end amplifier.

The duplexer's out-of-band impedance is an integral part of the PA design. The circuit is designed to protect the PA from ever seeing potentially damaging impedances.

A high-pass element of the duplexer TX branch also provides protection against Electro Static Discharge (ESD).

Receiver

The main components in the receiver include:

Receive front end

• ANNIKA IC

- Low Noise Amplifier (LNA)

- Mixer

• Bandpass filter IF section

• Bandpass filter - 45 MHz

• IF IC

- 2nd Mixer

- IF AMP

- RSSI circuit

• Bandpass filters (two) - 450 KHz

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Technical Description EN/LZB 119 2506 R1A

Receive Front End

See Figure 2-7. The receiver (RX) front end is the first link in the receiver chain. Its amplifies the RF and down-converts it to the first IF frequency. The desired frequencies are within the range of 869 to 894 MHz.

The received signal from the antenna is fed to ANNIKA via the duplexer. The LNA, in ANNIKA, is followed by an external bandpass filter (869-894 MHz). This filter is needed for spurious response rejection (suppression of the first image frequency). From the BP filter, the signal is then fed to the active mixer section of ANNIKA. The 1st LO (914-939 MHz) is generated from the RX VCO. Together with the RX synthesizer, ANNIKA down converts the received signal to 45 MHz (first IF).

The signal then proceeds to the IF section.

IF Section

See Figure 2-7. The IF section is the second link in the receiver chain, performing the major part of RF amplification and all the channel filtering.

The first IF (45 MHz) is filtered, buffered, and fed to the second mixer where it is down converted to 450 kHz (2nd IF) in the IF IC. The second LO (44.55 MHz), for the second mixer, is generated in BERTINDY by multiplying the 14.85 MHz VCTCXO signal by three.

From the IF section, the 450 kHz signal is filtered, then fed to the digital discriminator in BERTINDY for demodulation. The signal is also used in the AFC circuitry to determine frequency error of the 14.85 MHz reference relative to the received signal.

A received signal strength indicator voltage (RSSI) is generated by the IF IC, while the FM detection and RSSI A/D conversion is done in the BERTINDY ASIC.

Further audio processing of the discriminator signal is performed in the ANTON ASIC.

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EN/LZB 119 2506 R1A Technical Description

Synthesizer

The main components of the synthesizer include:

• VCTCXO

• BERTINDY

- RX (main) synthesizer (used for first LO signal)

- TX (auxiliary) synthesizer (used for 90 MHz signal)

- Reference divider

• MALIN

- TX VCO

- TX buffer stage

- TX mixer

- RX buffer stage

- RX prescaler

VCTCXO

A frequency reference signal of 14.85 MHz, common to the two synthesizers, is generated by a Voltage Controlled Temperature Compensated Crystal Oscillator (VCTCXO) and buffered in BERTINDY. This phone uses a discrete VCTCXO circuit with a 14.85 MHz crystal at its heart.

The task of the TCXO is to supply the synthesizer with a stable, accurate reference frequency. The TCXO frequency stability is controlled by DACs in BERTINDY. A software algorithm is used for temperature compensation as well as an automatic frequency control (AFC) function.

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Technical Description EN/LZB 119 2506 R1A

BERTINDY

BERTINDY is a new ASIC which combines the functions that both the BERTRAM and CINDY ASICs performed in previous generation phones.

BERTINDY performs the following functions:

• Control logic inputs and outputs from the microprocessor

• Output power detection and control

• Received signal strength (RSSI) A/D conversion

• 450 kHz signal prescaling (for AFC and data modem) to 54 kHz

• Discrimination of the 450 kHz frequency and filtering of the audio signal

• Buffering of the 14.85 MHz reference signal (VCTCXO) to synthesizers

• Control signals (D/A converted) to VCTCXO for frequency set

• Battery voltage A/D conversion

• A/D conversion of levels for handsfree audio

• Control of VTX/V

• Digital output to control power sources, synthesizer turn on/off, power

amplifier turn on/off

Serial data communication is used for the interface between BERTINDY and the logic section.

RX (Main) Synthesizer

The task of the RX (main) synthesizer is to supply the RX and TX mixers with local oscillator (LO) signals. The RX signal is 45 MHz above the chosen receiver frequency (1st RX IF). The TX signal is 90 MHz above the chosen TX frequency (TX IF). The desired frequency is set from the logic section.

The synthesizer's reference signal comes from the 14.85 MHz VCTCXO. The main synthesizer has a speed-up mode, which allows it to get a fast lock-in time at synthesizer start-up. This provides current savings by shutting down during repeated overhead messages.

The main synthesizer is locked if the radio can tune to a control channel and correctly decode the data being sent and correctly decode the SAT. On the TX synthesizer, the control voltage for the TX VCO is continuously monitored by the microprocessor to check that it is within an allowable range. If the control voltage outside the range, the TX is turned off.

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EN/LZB 119 2506 R1A Technical Description

TX (Auxiliary) Synthesizer

The task of the TX synthesizer is to supply the PA stage with the TX signal at the chosen transmitter frequency (824.04 - 848.97 MHz) in steps of 30 kHz. The reference for the TX synthesizer comes from the 14.85 MHz VCTCXO. The TX synthesizer creates a fixed 90 MHz signal by phase-locking a down-divided VCO signal to the 150 kHz reference signal. The local oscillator signal is then mixed with the 90 MHz signal to create the TX frequency signal. The TX synthesizer is programmed from the logic section.

MALIN

The MALIN ASIC contains the TX VCO, TX buffer stage, TX mixer, RX buffer stage, and RX prescaler. The TX VCO oscillates at a frequency determined by the voltage at the control input. The frequency can be controlled around 90 MHz. One part of the VCO output is fed back to the auxiliary (TX) synthesizer input of BERTINDY. The main part of the signal is fed to the TX mixer through a low pass filter. The signal is then mixed down with the 90 MHz TX signal to form the transmitter frequency. Then it is passed through a bandpass filter and fed to the discrete driver stage in the transmitter block.

Transmitter

The main component of the transmitter is the Power Amplifier (PA). The transmitted signal is generated by the transmit synthesizer (90 MHz) and can be

modulated by an audio signal. The transmit IF (90 MHz) is mixed with the RX_LO frequency to produce the correct transmit frequency. The signal is then fed into the power amplifier. The output power is controlled to the appropriate level by means of a feed back loop consisting of an op amp and a reference voltage from BERTINDY. From the PA, the signal is fed through the duplexer to the antenna.

Power Amplifier

The PA is a GaAs FET IC with high gain and efficiency. Controlling the input drive level varies the gain and output power. The saturated output power of the PA is dependent upon the load presented at its output. The PA will withstand severe mismatch (up to 7:1) at the PA output. The loss through the match, filter, and duplexer provides sufficient return loss to ensure less than 7:1. The PA is biased with negative voltage generated by the internal negative voltage supply.

NOTE

The PA is extremely sensitive to ESD and should not be

repaired, replaced, or probed without proper ESD-protected

equipment.

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Technical Description EN/LZB 119 2506 R1A

Logic Section

The main sections of the logic include:

• Processor/control interface

• Memories

• User interface

• Audio section

• Regulators

• Charging circuit

Processor/Control Interface

The main components of the processor/control interface include:

• GUSTAV

• 6303 Microprocessor

• ROM

• RAM

• Bus interface

• Decoder

• Serial interface

• External ports

• Watchdog

• BAR Generator

• Clock Generator

• Internal ports

• Modem

• Baudclock

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EN/LZB 119 2506 R1A Technical Description

GUSTAV

GUSTAV is an ASIC that replaces CARL (used in previous Ericsson models). GUSTAV is the heart of the Logic section and has most digital functions "on chip".

6303 Microprocessor

• 8-bit processor

• Asynchronous full duplex serial communication interface for external

connections

ROM

• 512 byte

• Contains an interface program used for loading code into the RAM

RAM

• 6016 bytes

• Used by the processor as "working space" when the phone is turned on

• When turning off the phone, data that has to be saved is stored in the

EEPROM

Bus Interface

• Generates the data and address lines to the EPROM and internal

RAM/ROM

• Handles the internal busses in GUSTAV

Decoder

• An address decoder with address map

• Has outputs for both internal GUSTAV functions and logic control

signals

Serial Interface

• Has a transmitter block and a receiver block

• The transmitter block consists of four write registers, a clock divider, and

other logic for generating interrupts and latch signals

• The receiver block consists of three read registers in which the received

data may be read by the processor

External Ports

• Manages the keyboard along with handling binary input and output ports

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Technical Description EN/LZB 119 2506 R1A

Watchdog On/Off

• Contains the watchdog block and the autonomous time out

• The watchdog block consists of a counter that, when overflowed,

activates a reset circuit.

• The autonomous time-out (ATO) is a supervising block that monitors the

status of the received carrier detect (RXCD) and transmitter power. If TX power is detected without the RXCD for 30 seconds, the ATO turns off the phone.

Beep, Alarm, Ring (BAR)

• Generates a signal that can have varying tones and volumes

• The ON and OFF time can vary between 7.9 us and 2.02 ms

Clock Generator

• 8.064 MHz signal from BERTINDY is divided down and gives a system

clock frequency (E-clock) of 2.016 MHz

• Has many divider steps to generate all clock frequencies that are

necessary inside GUSTAV and other parts of the logic

Silent Ring (AF778 Only)

• A 2mA signal is sent from GUSTAV, divided down and filtered to

prevent drive circuit oscillations and ESD damage

• Signal is then sent to the vibrator motor to activate a silent ring, and to

the LED to activate the orange indicator light

Internal Ports

• Three 8-bit read and three 8-bit write ports that are used within

GUSTAV

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EN/LZB 119 2506 R1A Technical Description

Modem

Consists of:

• Data receiver

- Discriminator

- Data decoder

- Wordsync detector

• Data transmitter

• SAT detector

- SAT detection is continuous. Each measurement is 10-12 ms for the three frequencies used (5970, 6000, and 6030 Hz).

• SAT transmitter

- SAT generation of the three frequencies

Baudclock

• Generates the baud rate (9600) for the serial interface of GUSTAV

Memories

The main components for memory include:

• RAM

• ROM

• EPROM

• EEPROM

RAM

Internal to GUSTAV.

ROM

Internal to GUSTAV.

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Technical Description EN/LZB 119 2506 R1A

EPROM (Flash)

The EPROM is a flash PROM with a 128k by 8 bit area. The phone's operating software is stored here. Software is loaded via a serial channel into Flash EPROM. The main purpose of software is to:

• Control the hardware circuitry

• Communicate with the cellular system via the RF link

• Provide and handle the operating interface to the user

• Overall system coordination (the phone's operating system)

• Charging of the battery

NOTE

This Flash PROM may be replaced, in time, with a one-time

programmable PROM.

EEPROM

The EEPROM is a "customer" PROM. It is a CMOS component with a 4k by 8 bit area. Data that must be saved when the phone is turned off is stored in this memory. The EEPROM contains the telephone number, short numbers, talk time, feature set, and calibration information/values. The EEPROM is communicated with via a controller in GUSTAV.

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EN/LZB 119 2506 R1A Technical Description

User Interface

The main components of the user interface include:

• LCD

• Keyboard

• Buzzer

• Vibrator Motor

• Illumination

LCD

The display is a one-row LCD. It uses chip-on-glass technology for mounting the driver chip onto the LCD module. No negative voltage supply is required for this LCD. Past products used a negative voltage supply to adjust the contrast of the display because LCD technology, at the time, could not provide a viewing cone wide enough to support all viewing angles. The LCD in this phone uses technology that provides a much wider viewing cone, thereby eliminating the need for contrast control.

An elastomeric connector is used for contact between the LCD module and the PCB. Software to drive each display is contained in flash EPROM. The same version

operating software for the phone accommodates both types of LCD.

Keyboard

The basic keyboard pattern is printed on the gold plated PCB, which ensures contact. There is also a connection for different keyboard layouts. Besides the keyboard matrix, connections exist for illumination LEDs.

Buzzer

A buzzer in the transceiver generates the acoustic signals. The buzzer is an electromagnetic resonance type. It has a resonance frequency of about 3 kHz. The buzzer generates Beep, Alarm, and Ringing signals. The sounds are generated in GUSTAV by software control and transmitted to the buzzer on the BAR signal.

The acoustic level as well as the frequency of the signal is variable. The user can turn off all signals to the buzzer via the User Menu options. The different acoustic signals are:

• Ringing signals

• Alarm signals

• Low battery warning

• Keypad tone or click

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Technical Description EN/LZB 119 2506 R1A

Illumination

The phone is illuminated with 14 chip LEDs: four for the display and ten for the keyboard. The LEDs are switched on and off from GUSTAV. A voltage regulating circuit is used to prevent changes in backlight intensity due to changes in battery voltage.

There is also a double chip LED on the top of the transceiver. Refer to Top Indicator.

Vibrator Motor (AF778 Only)

The vibrator motor is located in the rear assembly of the phone. It is activated through GUSTAV when the phone is set to either Vibrate/Ring or Vibrate Only, and the phone receives a call.

Audio (Baseband) Section

The baseband audio processing circuitry is concentrated on the lower part of the PCB. The ANTON ASIC is the heart of the audio section. The main part of the audio frequency filtering and audio path switching is done in the ANTON ASIC.

ANTON performs the following analog functions:

• Audio filters

• Amplifiers

• Pre-emphasis and switches

• DTMF generator

• Handsfree circuitry

• Compressor/expander

Receive Audio

The discriminator output from BERTINDY is routed through a de-emphasis network where the received SAT is separated from the speech audio. Speech audio is routed to the speaker and SAT processing is done in GUSTAV.

The driver used for the earpiece speaker is also used to generate the Audio From Mobile Station (AFMS) signal. This signal is routed to the system connector for use by accessories and test equipment.

Transmit Audio

The microphone input, SAT tones, and data have separate signal paths and adjustments. They have no limiters. Adjustment is independent and does not interfere with audio deviation.

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EN/LZB 119 2506 R1A Technical Description

Power Supplies

Regulators

Three 50-mA regulators power the phone: VDIG, VMALIN, and VRAD. The VDIG regulator is used to power the digital, audio, and user interface circuitry. VMALIN powers Malin TX and buffer. VRAD powers the remaining radio circuitry. These regulators are on all the time (even during charging-only mode) except when the transceiver is turned off and not connected to a charger.

Reset

A low-voltage detector in ANTON monitors the digital voltage VDIG. While the phone is operating, if VDIG drops below 3.35V (typical), ANTON will cause the processor to reset. Upon power-up, this reset is held low for a 20 ms delay.

On/Off Control

The phone may be powered on by either pressing the END/PWR/NO key, or by applying 7v to 10v at DCIO.

The END/PWR/NO key powers the phone by connecting the voltage at VBATT to the regulator's enable input through a diode. The END/PWR/NO key must be held for at least 200 ms.

Chargers and accessories power the phone by applying 7v to 10v at DCIO. As with the END/PWR/NO key, the DCIO voltage must be present for at least 200 ms in order to power up the phone.

If the battery is dead (less than 4.0v), applying high voltage to DCIO will not power the phone immediately. The regulator enable is held low until the battery charges up to 4.2v via a trickle resistor. When the battery voltage reaches 4.2v, the regulators are enabled.

If a charger is not connected, the phone is powered off by holding, then releasing, the END/PWR/NO key. Pressing the END/PWR/NO key generates an interrupt to GUSTAV. The regulators will stay on until the END/PWR/NO key is released.

The phone does not turn completely off while a charger and battery are connected. The charging circuit will be active, and CHARGING ONLY will be displayed.

ERICSSON AF738, AF778 Technical Description CH2

Specifications and Main Features

Frequently Asked Questions

User Manual