Rainbow Electronics GE863-PY User Manual

GE863 Family Hardware User Guide

1vv0300783 Rev.0 - 10/06/08

This document is relating to the following products:

GE863-GPS 3990250660 GE863-GPS 3990250690

GE863 Hardware User Guide

1vv0300783 Rev.0 - 10/06/08

GE863-QUAD 3990250662 GE863-PY 3990250661

GE863-SIM 3990250700

NOTE: This document substitutes the following specifications:

• 1vv0300715 GE863-QUAD/PY Hardware User Guide

• 1vv0300714 GE863-GPS Hardware User Guide

GE863 Hardware User Guide

1vv0300783 Rev.0 - 10/06/08

Contents

1 Overview............................................................................................................................................ 7

2 GE863 Mechanical Dimensions....................................................................................................... 8

3 GE863 module connections.............................................................................................................. 9

3.1 PIN-OUT .................................................................................................................................................9

3.2 PINS LAYOUT

.....................................................................................................................................12

4 Hardware Commands..................................................................................................................... 13

4.1 Turning ON the GE863........................................................................................................................13

4.2 Turning OF

4.2.1 Hardware shutdown ...........................................................................................................................................15

4.2.2 Hardware Unconditional Shutdown (for GE863-GPS only)..............................................................................15

4.2.3 Hardware Unconditional Reboot (GE863-QUAD/PY/SIM only) .....................................................................17

F the GE863......................................................................................................................15

4.3 Power Supply ........................................................................................................................................19

4.4 Power Supply Requirements

4.5 General Design Rules

4.5.1 Electrical Design Guidelines..............................................................................................................................21

4.5.1.1 + 5V input Source Power Supply Design Guidelines ...............................................................................21

4.5.1.2 + 12V Input Source Power Supply Design Guidelines .............................................................................22

4.5.1.3 Battery Source Power Supply Design Guidelines .....................................................................................24

4.5.1.4 Battery Charge control Circuitry Design Guidelines ................................................................................25

4.5.2 Thermal Design Guidelines ...............................................................................................................................27

4.5.3 Power Supply PCB layout Guidelines...............................................................................................................28

...........................................................................................................................21

...............................................................................................................19

5 Antenna ........................................................................................................................................... 29

5.1 GSM Antenna Requirements ..............................................................................................................29

5.2 GSM Anten

na - PCB line Guidelines..................................................................................................30

5.3 GSM Anten

5.4 GPS Antenn

5.4.1 Combined GPS Antenna....................................................................................................................................31

5.4.2 Linear and Patch GPS Antenna..........................................................................................................................31

5.4.3 LNA and Front End Design Considerations ......................................................................................................32

na - Installation Guidelines .............................................................................................31

a Requirements................................................................................................................31

5.5 GPS Antenna - PCB Line Guidelines .................................................................................................33

5.6 GPS Antenn

5.7 Logic level specifications

5.7.1 Reset signal........................................................................................................................................................35

a - Installation Guidelines...............................................................................................33

......................................................................................................................34

6 Serial Ports...................................................................................................................................... 36

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6.1 GE863-GPS SERIAL PORTS .............................................................................................................36

6.2 GE863-QUAD/PY/SIM SERIAL PORTS ..........................................................................................36

6.3 MODEM SERIAL P

6.4 GE863-GPS secondary ports

6.4.1 MODEM SERIAL PORT 2 (GPS CONTROL) ................................................................................................39

6.4.2 GPS SERIAL PORT A (SIRF BINARY)..........................................................................................................39

6.4.3 GPS SERIAL PORT B (NMEA).......................................................................................................................40

ORT ....................................................................................................................37

...............................................................................................................39

6.5 GE863-QUAD/PY/SIM secondary port..............................................................................................40

6.5.1 MODEM SERIAL PORT 2 (Python Debug).....................................................................................................40

6.6 RS232 Level Translation ......................................................................................................................41

6.7 5V UART level translation

...................................................................................................................44

7 Audio Section Overview.................................................................................................................. 46

7.1 INPUT LINES (Microphone) ..............................................................................................................48

7.1.1 Short description................................................................................................................................................48

7.1.2 Input Lines Characteristics ................................................................................................................................49

7.2 OUTPUT LINES (Speaker).................................................................................................................50

7.2.1 Short description................................................................................................................................................50

7.2.2 Output Lines Characteristics..............................................................................................................................51

8 General Purpose I/O....................................................................................................................... 52

8.1 GPIO Logic levels .................................................................................................................................54

8.2 Using a GPIO Pad as INPUT

...............................................................................................................55

8.3 Using a GPIO Pad as OUTPUT

8.4 Using the RF Transmission Control

8.5 Using the RFTXMON Output GPIO5

8.6 Using the Alarm Output

8.7 Using the Bu

zzer Output GPIO7 ........................................................................................................57

GPIO6 .........................................................................................................56

8.8 Magnetic Buzzer Concept

8.8.1 Short Description ...............................................................................................................................................58

8.8.2 Frequency Behaviour.........................................................................................................................................59

8.8.3 Power Supply Influence.....................................................................................................................................59

8.8.4 Warning .............................................................................................................................................................59

8.8.5 Working Current Influence................................................................................................................................59

..........................................................................................................55

GPIO4 ......................................................................................55

................................................................................................55

s ..................................................................................................................58

8.9 Using the Temperature Monitor Function.........................................................................................60

8.9.1 Short Description ...............................................................................................................................................60

8.9.2 Allowed GPIO ...................................................................................................................................................60

8.10 Indication of network service availability ..........................................................................................61

9 RTC and Ausiliary supply .............................................................................................................. 62

9.1 RTC Bypass out ....................................................................................................................................62

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9.2 VAUX1 power output...........................................................................................................................62

10 PPS GPS Output (GE863-GPS only)............................................................................................. 63

10.1 Description ............................................................................................................................................63

10.2 Pulse Characteristics

............................................................................................................................63

11 DAC and ADC section .................................................................................................................... 64

11.1 DAC Converter .....................................................................................................................................64

11.1.1 Description ....................................................................................................................................................64

11.1.2 Enabling DAC ...............................................................................................................................................65

11.1.3 Low Pass Filter Example...............................................................................................................................65

11.2 ADC Converter .....................................................................................................................................66

11.2.1 Description ....................................................................................................................................................66

11.2.2 Using ADC Converter ...................................................................................................................................66

12 Mounting the GE863 on the Application Board ........................................................................... 67

12.1 General ..................................................................................................................................................67

12.1.1 Module Finishing & Dimensions ..................................................................................................................67

12.1.2 Recommended foot print for the application .................................................................................................68

12.1.1 Suggested Inhibit Area ..................................................................................................................................69

12.1.2 Debug of the GE863 in Production ...............................................................................................................70

12.1.3 Stencil............................................................................................................................................................70

12.1.4 PCB pad Design ............................................................................................................................................71

12.1.5 Solder paste ...................................................................................................................................................73

12.1.6 GE863 Solder Reflow....................................................................................................................................73

12.1.7 Packing System .............................................................................................................................................75

12.1.8 Moisture Sensibility.......................................................................................................................................77

13 Conformity Assessment Issues ....................................................................................................... 78

14 SAFETY RECOMMANDATIONS ................................................................................................ 79

15 Document Change Log................................................................................................................... 80

GE863 Hardware User Guide

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DISCLAIMER

The information contained in this document is the proprietary information of Telit Communications S.p.A. and its affiliates (“TELIT”). The contents are confidential and any disclosure to persons other than the officers, employees, agents or subcontractors of the owner or licensee of this document, without the prior written consent of Telit, is strictly prohibited.

Telit makes every effort to ensure the quality of the information it makes available. Notwithstanding the foregoing, Telit does not make any warranty as to the information contained herein, and does not accept any liability for any injury, loss or damage of any kind incurred by use of or reliance upon the information.

Telit disclaims any and all responsibility for the application of the devices characterized in this document, and notes that the application of the device must comply with the safety standards of the applicable country, and where applicable, with the relevant wiring rules.

Telit reserves the right to make modifications, additions and deletions to this document due to typographical errors, inaccurate information, or improvements to programs and/or equipment at any time and without notice. Such changes will, nevertheless be incorporated into new editions of this document.

GE863 Hardware User Guide

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1 Overview

The aim of this document is the description of some hardware solutions useful for developing a product with the

GE863-GPS / QUAD / PY / SIM modules.

Telit

In this document all the basic functions of a mobile phone will be taken into account; for each one of them a proper hardware solution will be suggested and eventually the wrong solutions and common errors to be avoided will be evidenced. Obviously this document cannot embrace the whole hardware solutions and products that may be designed. The wrong solutions to be avoided shall be considered as mandatory, while the suggested hardware configurations shall not be considered mandatory, instead the information given shall be used as a guide and a starting point for properly developing your product with the Telit

SIM modules. For further hardware details that may not be explained in this document refer to the Telit GE863

Product Description document where all the hardware information is reported.

NOTICE

(EN) The integration of the GSM/GPRS GE863-GPS/QUAD/PY/SIM cellular module within user application shall be done according to the design rules described in this manual.

(IT) L’integrazione del modulo cellulare GSM/GPRS GE863-GPS/QUAD/PY/SIM all’interno dell’applicazione dell’utente dovrà rispettare le indicazioni progettuali descritte in questo manuale.

(DE) Die integration des GE863-GPS/QUAD/PY/SIM GSM/GPRS Mobilfunk-Moduls in ein Gerät muß gemäß der in diesem Dokument beschriebenen Kunstruktionsregeln erfolgen

(SL) Integracija GSM/GPRS GE863-GPS/QUAD/PY/SIM modula v uporabniški aplikaciji bo morala upoštevati projektna navodila, opisana v tem piročniku.

(SP) La utilización del modulo GSM/GPRS GE863-GPS/QUAD/PY/SIM debe ser conforme a los usos para los cuales ha sido deseñado descritos en este manual del usuario.

(FR) L’intégration du module cellulaire GSM/GPRS GE863-GPS/QUAD/PY/SIM dans l’application de l’utilisateur sera faite selon les règles de conception décrites dans ce manuel.

GE863-GPS / QUAD / PY /

GE863-GPS/QUAD/PY/SIM

The information presented in this document is believed to be accurate and reliable. However, no responsibility is assumed by Telit Communications S.p.A. for its use, nor any infringement of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent rights of Telit Communications S.p.A. other than for circuitry embodied in Telit products. This document is subject to change without notice.

GE863 Hardware User Guide

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2 GE863 Mechanical Dimensions

The Telit GE863 modules overall dimension are:

• Length: 41,4 mm

• Width: 31,4 mm

• Thickness: 3,6 mm

GE863 Hardware User Guide

3 GE863 module connections

3.1 PIN-OUT

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BGA

Ball

Signal I/O Function

GPIO13 I/O GPIO13 CMOS 2.8V

GPIO12 I/O GPIO12

GPIO11 I/O GPIO11

GPIO10 I/O GPIO10 CMOS 2.8V

GPIO9 I/O GPIO9 CMOS 2.8V

GPIO8 I/O GPIO8 CMOS 2.8V

RESERVED - RESERVED -

GND - Ground Power

EAR_MT- AO Handset earphone signal output, phase - Audio

EAR_MT+ AO Handset earphone signal output, phase + Audio

EAR_HF+ AO Handsfree ear output, phase + Audio

EAR_HF- AO Handsfree ear output, phase - Audio

MIC_MT+ AI Handset microphone signal input; phase+ Audio

MIC_MT- AI Handset microphone signal input; phase- Audio

MIC_HF+ AI Handsfree microphone input; phase + Audio

MIC_HF- AI Handsfree microphone input; phase - Audio

GND - Ground Power

SIMCLK O External SIM signal – Clock 1.8/3V ONLY

SIMRST O External SIM signal – Reset 1.8/3V ONLY

SIMIO I/O External SIM signal - Data I/O 1.8/3V ONLY

SIMIN I/O External SIM signal - Presence (active low)

SIMVCC - External SIM signal – Power 1.8/3V ONLY

ADC_IN1 AI Analog /Digital converter input A/D

VRTC AO VRTC Backup capacitor Power

TX_TRACE TX data for GPS control (TX data for Debug in case of

GE863-QUAD/PY/SIM)

RX_TRACE RX data for GPS control (RX data for Debug in case of

GE863-QUAD/PY/SIM)

VBATT - Main power supply Power

Internal

Pull up

47KΩ

4.7KΩ

47KΩ

CMOS 2.8V

Type

BGA

Ball

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Signal I/O Function

GND - Ground Power

STAT_LED O Status indicator led CMOS 1.8V

AXE I Handsfree switching

VAUX1 - Power output for external accessories -

GPIO4 I/O GPIO4 Configurable general purpose I/O pin /

GPIO2 / JDR I/O GPIO2 Configurable general purpose I/O pin / Jammer

Detect Output

GPIO1 I/O GPIO1 Configurable general purpose I/O pin CMOS 2.8V

CHARGE AI Charger input Power

GND - Ground Power

C103/TXD I Serial data input (TXD) from DTE CMOS 2.8V

C104/RXD O Serial data output to DTE CMOS 2.8V

C108/DTR I Input for Data terminal ready signal (DTR) from DTE CMOS 2.8V

C105/RTS I Input for Request to send signal (RTS) from DTE CMOS 2.8V

C106/CTS O Output for Clear to send signal (CTS) to DTE CMOS 2.8V

C109/DCD O Output for Data carrier detect signal (DCD) to DTE CMOS 2.8V

C107/DSR O Output for Data set ready signal (DSR) to DTE CMOS 2.8V

C125/RING O Output for Ring indicator signal (RI) to DTE CMOS 2.8V

GND

Ground Power

Internal

Pull up

100KΩ

4.7KΩ

CMOS 2.8V

Type

ON_OFF* I Input command for switching power ON or OFF (toggle

command).

RESET* I Reset input

GND - Ground Power

ANTENNA O GSM Antenna output - 50 ohm RF

GND - Ground Power

GPIO7 /

BUZZER

PWRMON O Power ON Monitor CMOS 2.8V

GPIO5

RFTXMON

GPIO6

ALARM

GPIO3 I/O GPIO3

GND - Ground Power

RESERVED - RESERVED -

CLK I/O Python Debug (CLK) (1) CMOS 2.8V

GPIO17 I/O GPIO CMOS 2.8V

GPIO14 I/O GPIO -

I/O GPIO7 / BUZZER output CMOS 2.8V

I/O GPIO5 / RF TX_ON signalling output CMOS 2.8V

I/O GPIO6 / ALARM output CMOS 2.8V

47KΩ

Pull up to VBATT

CMOS 2.8V

GE863 Hardware User Guide

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BGA

Ball

83 84

Signal I/O Function

MRST I/O Python Debug (MRST) (1) -

RESERVED - RESERVED -

DAC_OUT O DAC out

GPIO16 I/O GPIO CMOS 2.8V

RESERVED - RESERVED -

MTSR I/O Python Debug (MTSR) (1) -

GND - Ground Power

TX_GPS - GPS serial Port (TX) (1) -

GND - Ground Power

RESERVED - RESERVED -

GPIO15 I/O GPIO -

GND - Ground Power

RX_GPS - GPS serial Port (RX) (1) -

RESERVED - RESERVED -

PPS O 1 Pulse per Second signal (1) 100kOhm pull

GPIO18 I/O GPIO -

GND - Ground Power

RX_GPS_BIN - GPS serial Port (RX) – SIRF BINARY (1) CMOS 2.8V

GND - Ground Power

TX_GPS_BIN - GPS serial Port (TX) – SIRF BINARY (1) CMOS 2.8V

RESERVED - RESERVED -

GND - Ground Power

GPS_ANT - GPS ANTENNA (1) GND_GPS - GPS_ANTENNA GND (1) Power

Internal

Pull up

down

NOTES:

(1) Available only on GE863-GPS (in case of GE863-QUAD/PY/SIM it has to be considered

RESERVED)

Type

CMOS 2.8V

3.2 PINS LAYOUT

GE863 Hardware User Guide

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TOP VIEW

GE863 Hardware User Guide

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4 Hardware Commands

4.1 Turning ON the GE863

To turn on the GE863 the pad ON# must be tied low for at least 1 second and then released. The maximum current that can be drained from the ON# pad is 0,1 mA. A simple circuit to do it is:

ON#

Power ON impulse

GND

NOTE: don't use any pull up resistor on the ON# line, it is internally pulled up. Using pull up resistor may bring to latch up problems on the GE863 power regulator and improper power on/off of the module. The line ON# must be connected only in open collector configuration.

NOTE: In this document all the lines that are inverted, hence have active low signals are labelled with a name that ends with a "#" or with a bar over the name.

NOTE: The GE863 turns fully on also by supplying power to the Charge pad (Module provided with a battery on the VBATT pads).

TIP: To check if the device has powered on, the hardware line PWRMON should be monitored. After 900ms the line raised up the device could be considered powered on. PWRMON line rises up also when supplying power to the Charge pad

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For example: 1- Let's assume you need to drive the ON# pad with a totem pole output of a +3/5 V microcontroller (uP_OUT1):

10k

2- Let's assume you need to drive the ON# pad directly with an ON/OFF button:

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4.2 Turning OFF the GE863

The turning off of the device can be done in three ways:

• by software command (see GE863 Software User Guide)

• by hardware shutdown

• by Hardware Unconditional Shutdown

When the device is shut down by software command or by hardware shutdown, it issues to the network a detach request that informs the network that the device will not be reachable any more.

4.2.1 Hardware shutdown

To turn OFF the GE863 the pad ON# must be tied low for at least 2 seconds and then released. The same circuitry and timing for the power on shall be used. The device shuts down after the release of the ON# pad.

TIP: To check if the device has powered off, the hardware line PWRMON should be monitored. When PWRMON goes low, the device has powered off.

4.2.2 Hardware Unconditional Shutdown (for GE863-GPS only)

To unconditionally Shutdown the GE863-GPS, the pad RESET# must be tied low for at least 200 milliseconds and then released. The maximum current that can be drained from the ON# pad is 0,15 mA. A simple circuit to do it is:

Unconditional Shutdown impulse

RESET#

GND

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NOTE: don't use any pull up resistor on the RESET* line nor any totem pole digital output. Using pull up resistor may bring to latch up problems on the GE863-GPS power regulator and improper functioning of the module. The line RESET* must be connected only in open collector configuration.

TIP: The unconditional hardware shutdown should be always implemented on the boards and software should use it as an emergency exit procedure.

For example: 1- Let's assume you need to drive the RESET# pad with a totem pole output of a +3/5 V microcontroller (uP_OUT2):

10k

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4.2.3 Hardware Unconditional Reboot (GE863-QUAD/PY/SIM only)

To unconditionally Reboot the GE863-QUAD/PY/SIM, the pad RESET# must be tied low for at least 200 milliseconds and then released. The maximum current that can be drained from the ON# pad is 0,15 mA. A simple circuit to do it is:

Unconditional Reboot impulse

GND

NOTE: don't use any pull up resistor on the RESET* line nor any totem pole digital output. Using pull up resistor may bring to latch up problems on the GE863-QUAD/PY/SIM power regulator and improper functioning of the module. The line RESET* must be connected only in open collector configuration.

TIP: The unconditional hardware reboot should be always implemented on the boards and software should use it as an emergency exit procedure.

RESET#

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For example: 1- Let's assume you need to drive the RESET# pad with a totem pole output of a +3/5 V microcontroller (uP_OUT2):

10k

GE863 Hardware User Guide

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4.3 Power Supply

The power supply circuitry and board layout are a very important part in the full product design and they strongly reflect on the product overall performances, hence read carefully the requirements and the guidelines that will follow for a proper design.

4.4 Power Supply Requirements

POWER SUPPLY

Nominal Supply Voltage 3.8 V Max Supply Voltage 4.2 V Supply voltage range 3.4 V - 4.2 V

GE863-GPS

Mode Average [mA] Mode description

IDLE mode with GPS OFF

AT+CFUN=1 24,0 Normal mode: full functionality of the module AT+CFUN=4 22,0 Disabled TX and RX; module is not registered on the network

Power saving: CFUN=0 module registered on the network and can receive voice call or an SMS; but it is not possible to send

AT+CFUN=0 or

AT+CFUN=5

IDLE mode with GPS ON2 full power mode

AT+CFUN=1 113,0 AT+CFUN=4 111,0

IDLE mode with GPS ON trickle power mode

AT+CFUN=1 64,0 AT+CFUN=4 62,0

IDLE mode with GPS ON push to fix mode

AT+CFUN=1 24,0 AT+CFUN=4 22,0 AT+CFUN=5 10,0

RX mode

1 slot in downlink 53,0 2 slot in downlink 65,0 3 slot in downlink 78,0 4 slot in downlink 91,0

GSM TX and RX mode GPS ON

Min power level 135,0

Max power level 254,0

GPRS (class 10) TX and RX mode GPS ON

Min power level 187,0

Max power level 430,0

7,3 / 3,41

AT commands; module wakes up with an unsolicited code (call

or SMS) or rising RTS line. CFUN=5 full functionality with power

saving; module registered on the network can receive incoming

Stand by mode; no call in progress; GPS consumption reduced

Stand by mode; no call in progress; GPS performs a fix and then

Stand by mode; no call in progress; GPS OFF

calls and SMS

Stand by mode; no call in progress; GPS ON

maintaining the NMEA sentences

it switches off for the defined period

GSM Receiving data mode

GSM Sending data mode

GPRS Sending data mode

Worst/best case depends on network configuration and is not under module control

The values reported are with GPS antenna current consumption (22mA) included

GE863 Hardware User Guide

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In case of GE863-GPS with p/n 3990250690 the GPS consumptions are reduced by a 30%:

GE863-GPS (3 990 250 660) GE863-GPS (3 990 250 690)

Operating current

70 mA ±20%, including 50 mA for the

GPS hardware and 20 mA for the

antenna LNA

55mA, including 35mA GPS for the

GPS hardware and 20 mA for the

antenna LNA

GE863-QUAD/PY/SIM

Mode Average (mA) Mode description

IDLE mode

AT+CFUN=1 24,0 Normal mode: full functionality of the module AT+CFUN=4 22,0 Disabled TX and RX; module is not registered on the network

Power saving: CFUN=0 module registered on the network and can

receive voice call or an SMS; but it is not possible to send AT

AT+CFUN=0 or

AT+CFUN=5

RX mode

1 slot in downlink 53,0 2 slot in downlink 66,0 3 slot in downlink 79,0 4 slot in downlink 89,0

GSM TX and RX mode

Min power level 78,0

Max power level 200,0

GPRS (class 10) TX and RX mode

Min power level 124,0

Max power level 371,0

7,20 / 3,563

commands; module wakes up with an unsolicited code (call or

SMS) or rising RTS line. CFUN=5 full functionality with power

saving; module registered on the network can receive incoming

Stand by mode; no call in progress

calls and SMS

GSM Receiving data mode

GSM Sending data mode

GPRS Sending data mode

The GSM system is made in a way that the RF transmission is not continuous, else it is packed into bursts at a base frequency of about 216 Hz, and the relative current peaks can be as high as about 2A. Therefore the power supply has to be designed in order to withstand with these current peaks without big voltage drops; this means that both the electrical design and the board layout must be designed for this current flow. If the layout of the PCB is not well designed a strong noise floor is generated on the ground and the supply; this will reflect on all the audio paths producing an audible annoying noise at 216 Hz; if the voltage drop during the peak current absorption is too much, then the device may even shutdown as a consequence of the supply voltage drop.

TIP: The electrical design for the Power supply should be made ensuring it will be capable of a peak current output of at least 2 A.

Worst/best case depends on network configuration and is not under module control

GE863 Hardware User Guide

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4.5 General Design Rules

The principal guidelines for the Power Supply Design embrace three different design steps:

• the electrical design

• the thermal design

• the PCB layout.

4.5.1 Electrical Design Guidelines

The electrical design of the power supply depends strongly from the power source where this power is drained. We will distinguish them into three categories:

• +5V input (typically PC internal regulator output)

• +12V input (typically automotive)

• Battery

4.5.1.1 + 5V input Source Power Supply Design Guidelines

• The desired output for the power supply is 3.8V, hence there's not a big difference between the input source and the desired output and a linear regulator can be used. A switching power supply will not be suited because of the low drop out requirements.

• When using a linear regulator, a proper heat sink shall be provided in order to dissipate the power generated.

• A Bypass low ESR capacitor of adequate capacity must be provided in order to cut the current absorption peaks close to the GE863, a 100μF tantalum capacitor is usually suited.

• Make sure the low ESR capacitor on the power supply output (usually a tantalum one) is rated at least 10V.

• A protection diode should be inserted close to the power input, in order to save the GE863 from power polarity inversion.

An example of linear regulator with 5V input is:

GE863 Hardware User Guide

1vv0300783 Rev.0 - 10/06/08

4.5.1.2 + 12V Input Source Power Supply Design Guidelines

• The desired output for the power supply is 3.8V, hence due to the big difference between the input source and the desired output, a linear regulator is not suited and shall not be used. A switching power supply will be preferable because of its better efficiency especially with the 2A peak current load represented by the GE863.

• When using a switching regulator, a 500kHz or more switching frequency regulator is preferable because of its smaller inductor size and its faster transient response. This allows the regulator to respond quickly to the current peaks absorption.

• In any case the frequency and Switching design selection is related to the application to be developed due to the fact the switching frequency could also generate EMC interferences.

• For car PB battery the input voltage can rise up to 15,8V and this should be kept in mind when choosing components: all components in the power supply must withstand this voltage.

• A Bypass low ESR capacitor of adequate capacity must be provided in order to cut the current absorption peaks, a 100μF tantalum capacitor is usually suited.

• Make sure the low ESR capacitor on the power supply output (usually a tantalum one) is rated at least 10V.

• For Car applications a spike protection diode should be inserted close to the power input, in order to clean the supply from spikes.

• A protection diode should be inserted close to the power input, in order to save the GE863 from power polarity inversion. This can be the same diode as for spike protection.

GE863 Hardware User Guide

1vv0300783 Rev.0 - 10/06/08

An example of switching regulator with 12V input is in the below schematic (it is split in 2 parts):

GE863 Hardware User Guide

1vv0300783 Rev.0 - 10/06/08

4.5.1.3 Battery Source Power Supply Design Guidelines

• The desired nominal output for the power supply is 3.8V and the maximum voltage allowed is

4.2V, hence a single 3.7V Li-Ion cell battery type is suited for supplying the power to the Telit GE863 module. The three cells Ni/Cd or Ni/MH 3,6 V Nom. battery types or 4V PB types MUST NOT BE USED DIRECTLY since their maximum voltage can rise over the absolute maximum voltage for the GE863-GPS and damage it.

NOTE: DON'T USE any Ni-Cd, Ni-MH, and Pb battery types directly connected with GE863. Their use can lead to overvoltage on the GE863 and damage it. USE ONLY Li-Ion battery types.

• A Bypass low ESR capacitor of adequate capacity must be provided in order to cut the current absorption peaks, a 100μF tantalum capacitor is usually suited.

• Make sure the low ESR capacitor (usually a tantalum one) is rated at least 10V.

• A protection diode should be inserted close to the power input, in order to save the GE863 from

power polarity inversion. Otherwise the battery connector should be done in a way to avoid polarity inversions when connecting the battery.

• The battery capacity must be at least 500mAh in order to withstand the current peaks of 2A; the suggested capacity is from 500mAh to 1000mAh.

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